On a 7-9, Madison will let you in if you turn her on.

Madison puts her mouth back on you and licks you clean, tickling your balls again. That little extra attention firms you up again.

She pulls her head back and looks up on you. "God, was that crazy or what?" she says, laughing. Her bright red hair swishes in waves as she shakes her head. "But it was fun."

"I'll tell you what's more fun," you say. "You got me going. Now let me inside."

Madison's face goes blank. "You mean?"

"Me, into you," you say. "Let's do it."

Her mouth curls. "Like I don't know how that's gonna go," she says. "You gotta do something for me first."

"Yeah?" you say.

"Taylor told me never to let a guy inside who won't go down on me," Madison says.

"Deal," you say. "How about your room?"

"Move over, I need to get my wash started," she says.

Madison carefully measures out some laundry detergent and fills the washing machine with a load of her athletic clothes. She's running every day, so she goes through socks, underwear, shorts, and especially sports bras. Her cupcakes show off well in the elasticized support harnesses she wears. Some guys go crazy for the shiny sexy look, silky and lacy and pushed up, but more and more you're liking the look of women who feel comfortable wearing their own bodies and something simple that lets them move.

You hover behind Madison, feeling the warmth from her skin as she finishes preparing her wash load. She finally peels off her damp sports bra and drops it in, closing the door and starting the wash cycle. Now all she's wearing is a pair of white cotton plush shorts.

You follow Madison to her room. When she opens the door, she turns back to look at you. You step up and press her to the doorframe. Your bare chest presses against hers and your erection prods the front of her plush shorts. You look in Madison's eyes. The expression on her face is excited but uncertain, and her mouth twitches like she's about to break out in a crooked grin at how ridiculous it all is.

So you kiss her. Her body quivers against yours in a funny rhythm. She's laughing inside. But she kisses you back. Feeling her skin against yours, she's still warm from her run. You trace your fingers along her hair, feeling the dampness of her scalp. The scent of her sweat tickles your nose, and your cock throbs harder.

You walk her into the room, holding her in your arms, and kick the door closed behind you.

When you pull back and look at her face, it's flushed bright pink.

"I can't believe it, Tom," she says. That in-between look is on her face again. But her little pink raspberry nipples are swollen and stiff, pointing out at you.

"Are you still okay?" you ask. "Do you still want it?"

Madison swallows. "Yeah, I do. But is it okay, I mean, if I don't look at you?"

"Yeah," you say, nodding. "So did you want me to...?"

"I'll just put my head on the pillow, will that work?" she says.

"Sure," you say.

"Okay, turn away for a sec," Madison says.

You hear her pulling back sheets and peeling off what little she's still wearing.

"Okay," Madison says, a little muffled.

You turn around and find your sister face down on her bed on her knees, legs slightly apart, with her head and shoulders down, red tresses of hair snaking out across her pillow.

Madison's creamy backside is up and on display for you, the smooth, tight curves only interrupted by a few freckles and the crease from her shorts' elastic waistband. Her anus is a tightly knotted little pink star. Her inner lips are deep pink, swollen and slightly parted between the sparse red hairs on either side of her pussy.

You get behind her on the bed, cupping her firm buttocks in your hands, and lean close. You feel her pussy radiating warmth on your face. The heat of exercise amplifies her natural scent, strong and musky in your nose. You start kissing. The tails of her bush tickle your chin. You reach with your tongue, spreading her lips open. Warm and salty, sweaty and a little sour. As you lick, you hear Madison whimpering into the pillow. Her pussy lips grow wet with a flow of sweet, slippery juices. Her hips quiver as you lick harder and faster. When you find her clit, her hips jolt in a little earthquake and she moans loudly. Keeping your tongue licking over that hot little dot sticking up from her folds, you hear moans and squeaks and some noises you'd never expect to come out of Madison. As you're getting ready to come up for air, Madison shoots one hand back and grabs you by the hair, holding your face tight to her pussy. You carry on, right there, right there, right there, until Madison lets your head go. Her hips buck, thrusting backward and smacking your face with her wet pussy. She groans loudly with her climax, even with the pillow muffling her mouth. Her thrusting hips smack you twice more.

Taking this as your cue, you rise to your knees behind her and point your cock to Madison's pussy. It's a moving target, but very wet and open. You plunge into her hot depths.