I wasn’t finished, so I flipped her over and pressed my cock against her bottom and began to rub myself on her. Everything was OK, I was almost ther.... More grunts and sighs from Sam when I slid my hands under her to hold her breasts. I was right on the edge. One more stroke, perhaps two, no more than three and I’d be at the tipping point. I could feel it getting close.The back door slammed. I heard a gasp, a strangled gulp, and turned my head to look. Mom was standing on the back porch. What. Heather started kissing Jen on her lips and then was felling her tits.I smiled at Jen when she looked over and then saw, they both had their hands between each other’s legs and seemed really turned on. Heather had her hand up Jens skirt and was clearly fingering her ... Jen started to cum and Heather lowered her to the floor and started snogging her while still fingering her. When she calmed down, Heather straddled her head and lowered her pussy onto Jens face ... Another first, I watched as. My sister's golden-haired cunt with its pink fleshy lips contrasted with Jennifer's jet black hair-covered mound with dark pink, almost red, inner pussylips, thinner and hanging out from between the two fat rolls.Slowly, to give Jennifer time to react and stop me if she wanted to, I put my lips on the two flaps that hung down from her pussy and when my lips made contact with hers I felt that they were soft, very soft with just a hint of dampness. As I drew my tongue along the two meaty flaps. Almost ashamed of what I was doing, I masturbated to their moans, their cries of pleasure and the rhythmic movements of the bed above me, I heard a squeal that was Jenny, the scream became I scream and I ejaculated to the silence, to the unknown!I awoke to Jenny lying in my arms, her head on my chest and Karen shaking us both gently,"Come on you two" she said gently, "I'm going to cry in a minute"It was a spontaneous reaction as we reached out and pulled her into our embrace,"Jenny, you left.