I pressed the tip of my cock forward. I felt Jenna's tight asshole push back. I pressed a little harder and suddenly squuuuiiiip I was balls deep in my baby sister's ass. She let out a howl that couldn't be pleasure, but definitely wasn't pain.

"Oh ffffffuck!" she said.

I was so surprised at how easily it had all gone in, I almost fell forward. Grabbed at Jenna' thighs to hold me steady. I straightened up, my dick head-to-foot in the skinny brunette's butt. Jenna's body shifted back and forth slightly, and I realized that was Brianna, now jamming her twin's clit for all she was worth.

Jenna was gasping....