(noun) the guilt felt after getting off scott free from a questionable sexual experience.
note: although the experience will fade over time and often prove inconsequential in one's life, it will never truly go away and can resurface at any time, often causing a burning sensation one's moral fiber.
guy: oh my god, did you see the bacne on that butterface at the bar last night?
guy 2: dude, don't talk about it.
guy 1: why so sensitive?
guy 2: i just don't want to talk about it.
guy 1: wait, you never came home last night.
guy 2: i said i don't want to talk about it.
guy 1: holy crap. you didnt sleep with her, did you?
guy 2: (silence)
guy 1: dude, thats disgusting.
guy 2: listen, man, the moral herpes is enough, thanks.