She wants it as much as you do.

As your fingers wiggle under her suit, and into her nethers, she groans at the invasion, arching her back. She's warm inside, and getting warmer; her heat is intoxicating. You pull your fingers out as you crawl over her, placing the tip of your penis at her opening while you hold her suit to the side.

Looking into your eyes, she gives a brief nod, and you slowly slide into her. Her eyes half close, and she grunts as if she's in pain. She makes no move to stop you though, and when you pause, she gives a small whimper.

Slowly but surely, you slide your erect member into her. She's obviously not a virgin, but she's still so tight you don't think you'll last very long at all. And so you try to go slow. Your plans are dashed as she wraps her legs around you, holding you tight as her hips match every thrust you make.

In and out, in and out, you plunder your baby sister's sweet pussy. You pinch her nipples through her suit, and she lets out a loud groan as she twitches, her pussy flooding with her cum.

You can feel yourself close to climax yourself, so you warn her "I'm gonna cum".

"Not inside... I'm ovulating.. please not inside..." she barely makes out, being unable to catch her breath.