I'm thinking in the back of my mind that if it were discovered I might get even more excited.

A best work that brings together perverted beauties who are in the next room, even though they have a drunken acquaintance in front of them... and who can suppress their voices and immerse themselves in sex in a situation where it's not surprising that they'll be found out at any time! "Maybe he's moaning... he's being careful and pretending not to notice..." My sexual desire is escalating even more excitement as I imagine the worst case scenario in my head. "No, I'll find out...but don't stop it?" A voice-bearing sex is intertwined with pretense!