Silently

You watch, the girls still working your cock as your best friend's little sister put a cum-soaked finger to Ellen's lips in a shushing motion. Ellen nodded, her pink nipples hard as diamonds. Mandy's finger trailed across her sister's cheek and down her neck, making her skin erupt in goosebumps. Her touch went to Ellen's collarbone and she pushed down, stepping closer. Their tits touched and Ellen sank to her knees. Slowly. Guided by Mandy's finger tips.

"There's a good girl," Mandy purred as Ellen sucked her sister's nipples on the way down. And then Ellen started kissing her down Mandy's ribs, her abs, over to the crest of her hip, and then you lost sight of her mouth for a moment. Mandy lifted her leg, putting her toes on her sister's shoulder while Ellen's mouth came into view again, this time in visible grinning as she ran her tongue over Mandy's pussy.

"Fuuuck..." both girls working your rod swore softly. It sounded more like a prayer than a curse and they kept ambiently twisting and stroking your cock while giving it occasional wet licks and sucks. All three of you were riveted, watching Ellen's mouth open and her tongue pushing her younger sister's pussy lips apart before her own lips engulfed it. The motions in her neck made it clear that she was making out with Mandy's twat. Sucking. French kissing. Slurping silently.

"Holy shit sis...." Mandy purred. "We should ahve been do....uhgn..." her voice caught and became ragged. "Doing...for years..."

"Oh my fuck I want a sister," said one of the two girls sucking your cock. You'd lost track of who said it; you weren't paying attention to them. You were watching as Ellen started playing with her own pussy while she slowly mouthfucked her sister's mound, and it was more amazing than any of the times you'd imagined it while jerking off.