Blowing off steam

So I shared a bed with my sister. And kissed her. The line between a relationship based on S&M and... something even more inappropriate with my sister... was becoming increasingly blurred. Fortunately it didn't immediately lead to anything. We didn't even kiss again that week. I say fortunately because come on, you can't really fuck your sister. That would change our lives forever and we'd be ruined if anybody ever found out.

Cassie seemed to feel the same way. That week when we were hanging out in the basement playing video games (for fun), one of her friends linked her to an Instagram page where they show pictures of an attractive man and woman posing together and you have to vote on if they're siblings or dating. Some of them are completely ridiculous, like a girl wearing a bikini and kissing a guy's neck in one picture, and she's jumped into his arms in the next shot, and they're glowing with happiness in every image. Then the reveal is that they're brother and sister.

"We should be on there," I joked as Cassie scrolled through the pictures on her phone and I watched.

"Don't be gross," she said, and rolled her eyes. It seemed like mixed messages to me... she wanted me to kiss her and sleep in her bed after I punished her, but incest was gross?

Then again I was coming to accept that my grasp of the feminine mind was actually not nearly as good as I'd thought it was. At work the women were talking about high heels that week and I made some comment like "If I was a woman I'd never wear high heels. I can't imagine torturing myself just to please men." I thought of it as a feminist comment, if you can believe it, but boy did that set them off. Apparently they only wear high heels for themselves and were completely incensed at the idea that they were doing it to look good for male tastes, even though every guy I know raves about how great high heels make women look.

That was becoming more and more typical of my experiences at work as the only male bank teller. Every day managed I managed to feel degraded in a new way, like when someone in the drive-thru lane called me "sweetie", or when our boss the bank manager gave us a presentation about the bank's maternity leave policies.

I was really not enjoying being a bank teller and was seriously thinking about becoming a cop. It's become such a politically charged thing but honestly I just wanted a job where I could help out and feel useful, I'll not get any more into it than that. Still, you can't just change careers overnight and for the time being I was a bank teller. I had to keep going in to work.

But working in that environment was leaving me in a lousy mood each day. That Friday I came home needing to blow off steam. I went right into Cassie's room after getting home. She was finishing up her stream so I crept over to her bed, careful to stay out of frame. None of the popular lady streamers like her mentioned that they had boyfriends or husbands, even though they all did. Presenting the illusion of being single was just a necessary evil even if they weren't actively flirting with their subscribers, so Cassie did the same. Of course I was her brother, but such subtleties would be lost if the internet saw a dude in the background as she streamed. I waited patiently as she screamed about cheaters in the game she was playing. Her on-air personality is being incredibly bratty one minute then sweet and feminine the next. So she's pretty much just being herself, right? It works for her though, I was pretty sure she'd make more money than me that month, even after the streaming company took its cut and we set aside money for her taxes.

She spent a few minutes calmly saying goodbye to her viewers for the day and hosting another gamer girl, then she swiveled around to me in her chair.

"Hey Mike!" she said, "How was work?"

"Shitty," I said, laying there on her bed in my slacks and a green collared shirt. Fucking business casual. I was hating everything about the bank teller life. "How was streaming?"

"Great," she said, "I got my 2,000th subscriber today. I almost cried on stream..."

"Aw that's great!" I said, going over to hug her chastely. Each one of those paid her just under three bucks a month after expenses. Yeah, she was gonna make more money than me this month, but I was genuinely thrilled for her. "You're doing so great Cass. Congrats on not crying. Any technical issues?"

She smiled and hugged me back, but kept it chaste on her part too. "Yeah thanks. I hate to look be such a girl on stream," she said about the crying. It made sense to me. "And the stream went fine today. For a once no technological malfuckups," she said, adding in one of her cute little made-up words. "Anyway what can I do to make you feel better?"

"You really don't have to," I said.

"Nah you just worked all day and came home feeling crappy," she said, "Besides, there's things that would make us both feel good."

I grinned. By now it was clear that she got off on the S&M as much as I did - literally, because I'd heard her masturbating after my harshest punishments of her.

"Well if you insist," I said. I hadn't punished her in almost a week at that point.

She made sure the webcam was off, we'd both seen the nightmare videos of streamers doing very embarrassing things in their room after they thought a stream was over, but she was pretty good as far as technology was concerned and it was definitely off. Even still she pointed it to the wall just to be super-sure. Then she undressed in front of me, getting totally naked. She spun around so I could see everything.

Maybe I was just imagining things, but Cassie looked hotter every time I saw her naked lately. Maybe it was that she wasn't just flashing me as a prank anymore. She kept herself perfectly hairless and her body was so fit from her daily exercise sessions. She was more of a sporty girl-next-door sort of attractive than the massive-ass thick girl look that's in vogue, but that was absolutely fine with me.

"The bruises are gone," I said, looking at her ass.

"You can put new ones there," she said. It was strange to punish her when she hadn't done anything wrong, in fact she was on her best behavior. Previously I'd punished her with some degree of anger for her having been an offensive brat. But I really needed to blow off some steam and I wasn't being too particular at the moment.

I stripped off my own clothes. "I cant wear this monkey suit any longer," I said, getting to my boxers. Then I said fuck it and slid them down too, standing naked in front of my naked sister on a hunch that she'd allow this. At any rate it felt good to flash her for a once. I liked showing a woman my body if she wasn't opposed to it. Which I didn't think she was.

Cass was surprised but just stood there quietly for a moment. "Are... are you going to rape me?" she asked.

I was shocked by her question but I said "What? No. Do you want me to?"

She stuck her tongue out. "Of course not, moron!" Ah, there's the Cass I knew and loved. I suppose going naked was a bit of a surprise to her, but I was in a certain kind of mood. The steam had built up and I had to blow it off.

I grabbed her by her hair and pushed her onto her bed. "Hey what's the big idea?" she asked as I pushed her onto the bed. As usual she had little ability to physically resist me even if she wanted to.

I held her body under me as I got atop her on the bed. We were both naked. I didn't know what I was doing, I really had no idea how to properly punish a woman in a S&M relationship. I was winging all of this.

She looked at me intensely and I wondered if she was actually going to tell me to rape her, the way she'd told me to choke her. But she didn't say anything as I held her down by her wrists and ankles. In this position I had the urge to take her no matter what she said. It would feel so good, probably for both of us, but definitely for me.

I looked at her lustfully. Still she said nothing, but she looked between my legs at my cock. I could rape her. I think I even wanted to on some level.

But I couldn't do it, not without her permission. Still, these urges made me want to hurt her even more, since she'd said I could do that. I spun her over quickly, easily flipping her body, then made her get up on her hands and knees. She was breathing heavily and seemed to be feeling a mixture of fear and excitement, which only aroused me more. I bent to the floor and took the belt off my discarded pants, then held it like a whip. I thought about all my frustrations and looked at Cassidy's ass. It wasn't flabby but she wasn't skin and bones either. It was perfect for spanking. I whips her the belt across both butt cheeks, more testing it out than trying to do my worst, and she just grunted. I hit her twice more, harder each time. She stay on all fours as still as she could, her fleshy ass jiggling as she took her spanking.

"You're getting good at taking spankings," I said excitedly.

"Thank you, master," she said.

She'd never called me that before and I assumed it must be part of the fantasy for her. There was a whole language and protocol for S&M and I didn't know any of it. Treating a willing woman like this turned me on, but I didn't want to be some nerd following 300 S&M rules. Seemed like I might as well play Dungeons and Dragons. But what guy wouldn't like to be called master, especially by a tamed brat?

"Yes I am your master, brat," I said, whipping her ass again with the belt. She clenched her fists against the bed and took it. I could whip her ass pretty hard, I realized, with the belt's flat, smooth surface I doubted I could break the skin no matter how hard I hit her. That turned me on a lot. I hit her several more times, hearing the bed shake, making Cassidy start to whimper. I used it like a whip, snapping it so I could hit her harder.

"You're taking this well, slave," I said. Maybe I was supposed to be an asshole during this, but fuck the rules. I loved how Cassie was behaving.

"Ooh, I'm your slave now? Not your brat?" she said, excited at those perverse words.

I whipped her ass again with a loud slapping sound.

"Yes, my sister, you're my slave," I said, "I decide how much pain you endure." She moaned in delight.

I hit her butt again, making her tits jiggle as the pain rippled through her body. Her flesh was bright red now.

I stood behind her, wanting to humiliate her. "You like showing me your butthole. Spread it wide open for your master."

Her hand flew up and she rested her weight on her chest to use both hands to spread open her butthole for me. "Ooh I can see inside you, slave, very good," I said, "I'm looking at your insides."

"Master!" she said, but held herself open still, "This is embarrassing!"

I could see her anal passage, almost pink in color. She was practically gaping herself for me.

"I finally found something that embarrasses you, huh, slave?"

"Yess master," she said, almost cooing.

"I get to see every part of you, I own you, Cassidy," I said.

She gasped.

"Yesss my brother owns me," she moaned. Cassie was so deep into this. It was perverse, but I just didn't care anymore.

"On all fours again, slave," I said excitedly, and she got up as commanded.

I whacked her ass again with the belt, as hard as I could this time. The leather slapped her flesh hard and she creamed in pain and delight at the same time.

I kept whipping her with the belt, knowing by now that she could take it. I turned every bit of her ass red. I whipped her so hard I was out of breath myself. She was sweating and panting for breath. At the end, when I was satisfied with the pain I'd given her, I noticed I had a raging boner. Hurting my sister had made me as hard as I could possibly get. I decided not to hide it. I felt no shame around Cassie now.

"Okay slave," I said, "You did well. I feel better now."

She collapsed on her bed, sweating and breathing hard now. "Will you rub some lotion on me, Mike?" she asked softly. "Please don't leave me alone."

"I'll never leave you again," I said, understanding by now how much she needed aftercare. I went to our bathroom and got the lotion and came back as fast as I could, my boner flopping between my legs. Cassie definitely saw it now, laying on her bed with her head tilted to look at me as I entered.

"You can use that lotion for something else if you need to," she said casually.

"Okay, thanks," I said, grinning at the excitement of her giving me that perverse permission. I rubbed the lotion on her ass carefully, figuring no need to cause her pain now. Still she winced. "Sorry, I guess I got carried away..."

"Don't be," she said, "I liked it, Mike. Especially because you seemed to really need to hurt me... but the pain itself is always good."

I blushed a little. It was nice to talk openly about it, though. If anybody could understand the way I felt, it was her, and vice versa. It was good for us to talk about it.

"Y-yeah," I said, carefully rubbing the lotion into her ass cheeks, "It feels so good to hurt you Cassie. I know it's fucked up... but like... I want to do it so bad sometimes. Only because you like it."

I mostly focused on her cheeks but I couldn't help running my fingers down her crack, tickling them over her asshole as I applied lotion even though it wasn't needed there. She didn't object.

"I know, Mike," she said, "Don't be ashamed. It's just the way some people are. I'm glad you don't want to just victimize women. Lord knows there's enough of that in this world."

"Yeah," I said, finishing up with the lotion. It was tempting to touch just a few inches lower, feel her pussy, which I could tell was sopping wet... but she didn't want that yet, if she'd ever want it. "I hate men who abuse women. That's why this is so fucked up... I never want to abuse you."

"I know," she said, "I'll tell you if it's ever something I don't like. I'm not shy about complaining, remember?"

"Yeah," I laughed, liking the way she'd put it, "Never stop being a brat some of time". I rolled onto my back and laying next to her. She was her stomach with her head still tilted to look at me. "Can I use the lotion for the other thing now?" I asked.

"Yeah," she said with a grin, "Feel free."

I really should have gone to my room to jerk off, but doing it in front of Cassie felt so exciting. I'd never done anything like this before with her. I started to jack off as casually as I could, using the lotion as lube. I was naked on my sister's bed, my naked sister watching as I masturbated. I knew it was very wrong, but I felt good anyway. I looked at her lotion-covered ass as I stroked myself.

Cassie's fingers were under her now, pleasuring herself too. I was glad this turned her on. I knew it was wrong, but we were adults and if she wanted to masturbate next to me, I was all for it. She looked so confident and happy as she rubbed herself, smiling contentedly and moaning. I stroked my cock and looked at her lovingly, feeling no same.

"You're the best sister ever," I blurted out as I got close.

She smirked, but said, "I love you, big brother.Thanks for whipping my bratty ass."

That was all I needed. I came, shooting ropes of cum on my chest. Cassie watched, seeing me orgasm for the first time, and brought herself off with fingers, whimpering contentedly as she came.

We lay there naked for a while, just looking at each other, and occasionally I'd look at her red ass, and she'd look at my cock or my cum. It felt wonderful. I felt no shame and I don't think she did either. I loved my sister. If we could go on like this for the rest of our lives, I'd be happy. But if she wanted more, I think I'd be happier.