Her arm went around my sister and she pulled her up for more kisses. Julie grabbed Katie's leg (behind the knee) and pulled her open wider for me. I raised myself onto my hands and knees and started sliding my cock in and out of my sister's partner as the two of them made out.

Ten minutes later, Katie came. Up to that point, I'd been fighting to stay hard after blowing my load on her vulva. When I felt (and watched) her cum, however, my cock and balls were suddenly committed to doing everything possible to pump out another load - this one INSIDE of my sexy lover.

I...