Billy tells Anna the truth about the gloves, and she has a challenge for him.

Billy was totally under Anna's spell at this point. He watched the outline of her fingers under her shirt playing with one of her nipples, then looked up at her face. Anna gazed down at him and licked her lips, and at that moment, he knew he had to have a blow job from her. Lust overcame his judgment, and he decided to tell her the truth.

"I wasn't exactly going easy on you…" Billy finally said. "The gloves were loaded."

"Loaded? With what?" Anna was confused, as she often was with anything sports-related.

"Weights…small ones, to make them hit harder," Billy explained.

"So..you rigged the fight, against yourself?" Anna asked. "You WANTED me to knock you out?" She sat back a little, processing this new information.

Billy considered how he wanted to answer her question. He could lie, and say that his mom offered him money to let Anna beat him. He could claim that he wanted Anna and Heather as regular sparring partners, but loaded the gloves to make it more even. He could even say that he had no idea the gloves were loaded until he investigated after his match with Anna.

But looking up at her, he knew it was no use trying to come up with a fake story on the fly. Anna had been a mock trial champion in high school, and had spent four years as an investigative reporter for the school newspaper. Now, she participated on a debate team at university--in French, no less. In short, she could tell when someone was lying, and she knew what questions to ask in order to prove it.

"Sort of…I had never been knocked out before, and I needed to know what it felt like," Billy finally admitted. "So I loaded up the gloves and boxed with Mom."

"Why with Mom?" Anna asked.

"I didn't want anyone on my team to be knocking me out, or spreading rumors that I had a glass jaw. I wanted it to be something I could just keep between me and Mom," he said.

Anna looked at him skeptically. "And how did the match go?" she asked.

Billy squirmed uncomfortably. "She beat me…knocked me out in two separate fights." He thought about the night after the second fight, when she had dommed him in bed, bullying him with the loaded gloves and making him agree to kiss her mesmerizing ass. Billy decided to leave that part of the story out.

Anna was doubtful. "How did the fights go? Were you trying your hardest?" she asked.

Billy sighed. "In the first one, I roughed her up a little and then let her hit me. That one hit hurt way more than I expected, and it stunned me enough for her next one to bring me down. In the second one, I tried a lot harder, and I was winning for a while, but then she faked me out and got me with an uppercut, and then after that she had no trouble knocking me out." Billy left out all Heather's taunting.

Anna leaned forward. "And what about our fight?" Clearly, she wanted to see their climactic matchup from Billy's eyes.

"Well…like I said, you've always been quicker at picking things up than me, so I was a little worried right from the start," Billy said. "Plus, you seem to be in pretty good shape, so I wasn't sure if I was going to be able to tire you out, and after a few minutes I knew I was actually getting tired faster."

"I thought I was imagining it," Anna murmured thoughtfully. Her hips moved ever so slightly on Billy's chest, and he could feel an intense warmth in between her thighs.

"And then…I know you didn't mean to taunt me, but that was what it felt like, and it was so humiliating I lost my cool," Billy said, thinking back to the wild swings he'd taken in hopes of stopping her comments, and the way she'd dodged them, making him look like a reckless amateur. "And then you threw that one great punch, and that was it for me." Shame washed over Billy as he finished narrating his defeat at Anna's hands.

Anna straightened up, half satisfied. "So, it was the loaded gloves that made me knock you out?" she asked thoughtfully.

"Yes," Billy said, putting the final nail in the coffin as far as keeping his obsession secret. "So….can I have that blow job?" he asked hopefully.

Anna leaned forward and grabbed Billy's chin, her hair hanging over him and brushing against his face, sending a thrill through his pinned body. "You don't understand…knocking you out was the hottest thing I've ever experienced," she whispered. "But only because it felt so real and so right. Now I know it wasn't real at all."

Anna looked down at Billy. "We have to have a rematch, with regular gloves. I have to know for sure that I'm better than you."

Billy's head was spinning. Did she really think she had a chance without the loaded gloves? Why? Did it matter, as long as he got to fight her again, and maybe get head? "And will you give me head afterwards?" he asked.

"Sure…if you win," Anna replied playfully. "Meet downstairs in two minutes!" She slipped off of him and left his room.

Billy quickly threw on a t-shirt and gym shorts, his hands shaking as he did so. Why was he so nervous? Anna had already knocked him out once, leaving him drooling on the floor…and without the loaded gloves, she was unlikely to be able to do so again. But…if she could, then it would mean she was actually better than him. That's what it was. Letting his sexy female family members beat him was a turn on…but having them do it against his will, he wasn't sure about. At least right now, all it did was scare and humiliate him.

He was back in the cleared-out living room within three minutes. Anna wasn't there. Did she stand him up? Was it a prank? Billy nervously stewed for another few minutes.

Then Anna appeared in the doorway, still in those tiny blue shorts but having traded the white t-shirt for an orange sports bra. Billy gaped at her bare belly, which was flat and toned, although without any visible abs. She tossed the loaded gloves to him.

Billy used a pair of scissors to cut open the gloves and remove the small weights. Anna used her sewing skills to quickly patch up the gloves, and they were ready to go.

Billy faced Anna for the second time that night, staring her down from about 8 feet away. She had her gloves up, higher and tighter than in the previous match, reflecting all that she'd already learned from watching him. Her fists blocked her face, and her arms blocked her breasts and ribs, leaving only her lower abs open to attack. In her stance, he could see a mixture of her traditional shyness and her newfound confidence.

He figured it was best to deal with her quickly, knowing her endurance and stamina might be better than his. He raised his gloves and advanced towards Anna, planning to hit her with a solid blow to the belly.

SMACK! Billy took a step backwards in shock. As he'd gone for her belly, she had hit him with an incredibly fast jab right to the nose. It was a weak punch, but so fast he hadn't had a chance to block it.

"Wow, these are much easier to use!" Anna exclaimed happily, giggling at the disappointed and humiliated look spreading across Billy's face. He hadn't considered the possibility that her fists would be much faster without the added weight.

Billy shook it off and went in for another punch to her belly. SMACK! Anna popped him in the face with another fast jab. This one stung enough to make his eyes water, and he backed off again. He stared at Anna in wonder. How had she gotten so good, so fast?

He realized he was going to have to treat her like he'd treat one of his normal opponents. She was tagging him as he was going for her stomach, so he was going to have to stop going for the long shot and just beat on her arms a little to tire her out and slow her down.

As he approached her a third time, she flicked out a third surprisingly fast jab, but this time Billy was able to get his fist in front of it and knock it away. With his other hand, he sent a quick left hook to Anna's face. Her free right hand was able to block it somewhat, but at the very least, it knocked her off balance.

Before he could capitalize on the opening his last punch had created, Anna threw herself back at him. She swung several wild hooks that he blocked with his arms and elbows. He was surprised how heavy the blows felt as she battered him, even without the loaded gloves. He grunted in pain, inspiring her to hit him even harder and drive him backwards.

Billy took a few steps backwards while continuing to absorb and block Anna's repeated blows. She wasn't giving him a chance to fight back, so his best plan was to weather the storm until she got a little tired, then start counterpunching.

Anna backed him up against the wall, and as his back hit the wall, his block slipped a little. Anna's next hook slammed into his ribs, causing him to gasp and flinch and drop his guard a couple inches. With her other hand, she punched him hard in the face, knocking his head back against the wall.

Billy knew he was in danger. If she hit him like that a few more times, he was toast. He stepped forward, wrapping his arms around Anna's shoulders and trying to put a lot of his weight onto her. Anna stumbled, but still managed to hit him with a couple sharp little hooks to his ribs as they twirled across the room.

Finally, Anna wrenched free of Billy and they separated, both breathing hard. Billy tried to ignore the burning pain in his ribs, while focusing on the rise and fall of Anna's breasts in her sports bra.

She frowned at him. "What was that? Was that even legal?" she asked.

"Yeah, it's called a clinch," Billy said.

"What's it for?"

"Boxers do it when they…" Billy realized she was making him admit that he was already losing, but it was too late. "…when they know they're in trouble."

"So I had you on the ropes basically?" she asked. He winced at her use of the expression, wondering if she even knew that it came from boxing.

"Yeah," he said, embarrassed. Luckily, this pause in the match had helped him recover significantly. Now it was time to go on the offensive.

He knew he would have to eat a couple punches to get what he wanted, and he did. As he bulled towards Anna, she hit him hard and fast, twice in the stomach and once in the face. But he gave just as good as he got, hitting her twice in her guard, once right on her cheek, and once on her stomach. Now it was Anna's turn to back up, though she circled in such a way that he wasn't able to pin her to the wall like she'd just done to him.

It didn't matter. Billy was bigger, stronger, and ultimately faster. He kept knocking her back, hitting her forearms, abs, and occasionally something softer. Once, he was able to hit her right in her tits, making them bounce and causing her to make a little squeak of pain.

He finally got her against a wall after she tried to dodge one of his fists and ran smack into the other. She made a little frightened gasp as she felt her back hit the wall.

Billy knew it was time. If he didn't knock her down now, he wasn't sure what would happen. He had definitely done some damage, but her endurance was proving superior to his.

He hit her with several big hooks down low, forcing her guard lower and lower as she tried to block his punches, with limited success. Then, abruptly, he swung at Anna with a straight punch right to the nose. It was like her jabs from earlier, but with a lot more weight behind it, and it knocked her silly and made her a little cross-eyed.

Anna swung a clumsy hook at Billy, which he dodged, then he hit her right in the chin with another hook. Anna's head jerked to the side and she stumbled. As she regained her balance, she left her flat belly completely open. Billy lunged in with his hardest punch of the fight, to her lower belly. It hit even a bit lower than he intended, about three inches below her belly button and right at the waistband of her shorts. It was too low for her abs to block it, and the punch caused her body to fold instantly.

"OOF!" Anna gasped. As Billy backed off, Anna's legs quivered and she held her belly with both hands, slowly crumpling to the ground with a quiet sob. She knelt on the floor, her hair covering her face.

Billy instantly felt bad. Anna had gone from triumphant warrior queen back to the timid bookworm she'd always been, in the space of maybe a minute. Still, he couldn't help staring at her cleavage in her revealing sports bra. His cock started to get hard as he imagined her sucking it, still on her knees from his **** beatdown.

He willed himself to stop thinking about it. He took a couple steps toward Anna to try to help her up. "I'm sorry--" he said as he put a hand out. But she was already struggling to her feet on her own.

"Not yet, but you will be," Anna said as she pushed her hair out of her face. Her expression was serious, and Billy realized that contrary to what he'd thought, Anna was far from done.

She rushed him again, taking several swings that hit his guard, the punches hard enough to bounce his own gloves off his face. Billy found himself backing up yet again in the face of Anna's ferocity.

One punch slipped through and hit his ribs, then another hit his face. "Guuhhh," Billy groaned, starting to get woozy. No! He had to beat her. He took a wild swing that missed completely. Anna punished him with a deep hook to his belly. "Ooohhhhfff," he moaned, wincing and trying to slide to the side. Anna put that to a stop with a straight punch to his jaw. This one he blocked partially, but it still rattled his brain.

As she pinned him up against the wall, Billy realized that he was losing badly. She was knocking his guard from side to side, slipping her punches through to his ribs and stomach and chest and face. He was still blocking some, but even that was slowing him down and fatiguing him. Her punches still weren't that strong, but they also weren't any weaker than they were at the beginning of the match.

Billy knew he had to clinch again. He leaned forward, attempting to wrap his arms around her bare shoulders again. Except this time, she expected it, and she was able to duck his arm, making him stumble forward and almost fall. She circled around him and nailed him with a hard punch right to the kidney as he staggered toward the center of the room.

As he turned to face her, she hit him right in the mouth with what was becoming her signature fast left jab. "Mmmf!!" He made a muffled grunt, feeling the warm feeling that meant his sister had just split his lip.

Now he was too slow to block most of her punches. Anna started wailing on him, hitting him at will with hooks to his midsection. Each one made him hunch over a little more, bringing his head down to her level. She switched gears and started going for his head. SMACK! Another left jab knocked his head back, and he suddenly couldn't see Anna clearly. SMACK! A right hook hit his cheek, jerking his head to the side and making the whole room go fuzzy.

He tried to focus on Anna but his vision was drifting as she beat him into submission. SMACK! SMACK! Her weak, inexpert punches were nonetheless more than enough to break him down. She was beating him without a built-in advantage. It was just what he had feared.

Billy's arms dropped as his will to fight Anna dissolved. So far, he hadn't really gotten hard during the match, but now the mental blocks were evaporating and his blood, proving useless elsewhere, was rushing to his rapidly hardening cock. He mentally surrendered to Anna. She had conquered him completely, proving she was the tougher fighter and the better boxer. He dismissed the hope of the blow job, and now merely prayed for the knockout to come quickly and painlessly. He only hoped she wouldn't be bored with him after this.

"Had enough?" Anna asked, breathing hard and pausing her barrage of punches to give him the opportunity to surrender.

"Nooo…." Billy moaned. They both knew the answer was yes, and that Billy posed no further threat to Anna. But Billy wanted…no, needed his sister to finish the job.

"Okay, you asked for it!" Anna said happily.

SMACK! SMACK! Anna hit him with two more jabs to the face, and now she could see the vacant look in his eye, could read the surrender in dropping of his arms. She wasn't going to let him off easy, though, not after that low blow.

Anna hit Billy with a hard punch to his softening belly. He moaned and leaned over, making his face a perfect target. Anna lined up an uppercut just like the one she'd used to knock him out in their last fight, putting her whole sexy body into it. CRACK! Her punch slammed into Billy's chin and his eyes went blank as he straightened up. This didn't quite do the job it had in their last match, since it was just a normal boxing glove. But she was already throwing what she knew would be the last punch, a wicked haymaker with her right hand. Billy's face hovered right in front of her, and he was way too foggy to see the punch coming.

"POW!" echoed through the room as her punch hit Billy's jaw. His eyes rolled up in his head as it jerked to the side, and he fell like a ton of bricks. His face came to rest right on top of Anna's bare foot, and she giggled.

"That wasn't too much different from our last match, was it?" Anna said brightly. "They certainly both ended the same way!"

She used her bare foot to flip Billy's limp body over onto his back. She saw his hard cock, and briefly considered giving him the blow job he'd asked for, knowing that he probably wouldn't wake up until after it was over. But was that fair? After all, she'd won the match, and to the victor go the spoils...