My sister likes to watch me fuck her boyfriend.

He heard her giggles and the accompanying male voice. Her sister had returned home with her latest conquest, she couldn't stand her curiosity and peeked through the door of her sister's bathroom. She entered without shame and sat on the toilet. What she saw surprised her, the man accompanying her was the neighbor, the boy who had always been her secret fantasy.  The moans of both stunned her and she didn't want to move away from the tableau.  They couldn't help but lower their hand to their crotch and began to touch each other at the sight of their sister sucking their neighbor's member.