Time to join them.

The pulsing of your prick is too much, and you must join in. Slowly you push the closet door open and creep over to the end of the bed. What a spectacular view. As Cindy again begins to tongue your wife's snatch Diane looks at you and cracks a wide smile. She places both hands on the back of Cindy's head, forcing it into her crotch further. That's your cue.

You climb on the bed, and move up behind Cindy. You press your erection against her still bikini covered ass, and reach around her to cup and knead her firm breasts. Cindy begins to move, apparently surprised by your touch, but Diane keeps her head firmly in place between her legs. You let Cindy's right breast go and take your hand to grab your engorged penis at its base, and begin to rub the head of it up and down Cindy's clit. But, you can't take this for long either. You grab the edge of her bikini bottom and pull it aside, take your prick and literally shove it into her pussy.

Cindy utters "Mmmph" as you slam your cock to its hilt. There was some initial resistance, and you realize she must have been a virgin still.

"Oh godddd! You're tight." you spew. "Jesus you feel so good." And after only a few strokes in Cindy's tight snatch you can't take any more. "I'm gonna come!"

With that said, Diane says "No. Not in her.", and lets go of Cindy's head. Cindy doesn't move, and now seems to be enjoying this **** on her virginity. But Diane begins to move out from under her and towards you.