“Doesn’t it feel good, Kristina? Much better than just fantasizing, Isn’t it?”
“Y-yes! Unh.. Oh, yes!”
I couldn’t believe I was actually, finally, fucking. Let alone fucking my sister’s boyfriend. And with her smiling in approval. It had started as them walking in on me by accident, in the throes of masturbating while staring at a bathing suit picture of him on my computer. I’d snuck it at the beach, and it had clearly showed the outline of his cock as he was coming out of the surf.
Now that cock was slowly pumping in and out of me, and I was going to cum a second time!
“I’m glad. Because I want you to do me a favor. You know I can’t take the pill, so I need some help a few days of the month when I’m at the height of my cycle. Cal needs a pussy to cum in pretty much every day, and I don’t want him looking anywhere else. I’d love it if you’d let him cum in yours.”
The fucking was so good, the feeling so amazing, I couldn’t really follow what she was saying. But something clicked in my brain about cycles. My sister and I, last time I’d known, were pretty perfectly in sync. And I couldn’t take the pill either.
“Wait-” I gasped, putting a hand up to push on Cal’s chest. “D-don-”
At that moment, he thrust forward hard, shoving himself balls-deep in me, letting out the sexiest groan I’d ever heard. I felt his cock expand inside me, and pulse. He was cumming in me! Maybe it was that liquid surge in my belly. Maybe it was the danger, but my body chose that moment to climax again, and my protest was completely forgotten as I ground against him, my inner muscles squeezing him for all they were worth, milking him dry.