Give it to her

Jessica is fully dedicated to getting Jacks load into her. He can feel the way she is sucking on his glistening cock head. She is trying to suck the essence out of his body. No way he can deny her this.
Still, he wonders, who this girl next to him is.

Looking over to the side he can't see any difference between Monica and Jessica. The same perfect breasts and skin color, same muscle tone, same hairstyle. Completely identical.

Jessica sees him looking over and starts deep throating Jacks cock.
"Uuuuuuhhhnnn", a deep guttural groan releases from Jacks heaving chest. "Shhhh, you're gonna wake her.", Jessica whispers, releasing Jacks cock in a swift motion. Jack grabs a pillow to bite on, as his orgasm was clearly impending.

His balls are boiling with cum, ready to release a torrent down his lover's throat. His hips bucking and muscles throbbing to release a wave of pleasure into the warm confinement of Jessica's waiting mouth.

Jack squeezes Jessica's arm tightly indicating he's close.

What Jack hasn't noticed is that Jessica is close too. The hot pulsating rod lodged firmly in her lips has made her incredibly aroused and she is already soaking the sheets under her sister.

"I need you inside me", Jessica proclaims, releases Jacks cock and climbs on Jacks' chest. The sudden cold rush of air is only a short intermezzo from Jessica's furious blowjob. He can't wait to be inside Jessica, although staying quiet while he would surely cum inside her, would be nearly impossible.

It is too late for those thoughts now. Jessica has already positioned his throbbing member at the entrance to her innermost core and is ready to plunge on his dick.