Every time she comes over I have to act normal while my brain is screaming. The way she laughs at his dumb jokes, how she stretches and her shirt rides up just enough, that little smirk she gives me when no one's looking... fuck. I keep "accidentally" walking into the kitchen when she's there in her tiny sleep shorts, stealing glances while pretending to grab water. At night I jerk off thinking about her riding me on his bed, biting my lip so I don't moan her name too loud. I know it's fucked up. But the guilt just makes it hotter.