1. A very trippy orgy, facilitated by drugs.
2. Drunken competition involving trying to see who can find the most circumcised guys in a night. Whether sleeping with them or just yanking down their trousers is the goal depends on house rules at the time. One notes sleeping with them distracts one from keeping an accurate running tally.
3. Game played in the dark, in which one participant attempts to identify others merely by the shape of their penises.
4. Actually going out to pick mushrooms, magic or otherwise. Asking clarification is advised if invited to go mushrooming.
"Hey, we're drunk, we're bored, we're all here... let's go mushrooming!"
Sue liked going mushrooming, but she didn't like losing track of the guys she'd found.