Pinch and Switch
When a group of male friends or strangers meet up in a bathroom and spontaneously start pinching the others' penises with homoerotic glee. The "switch" part comes from switching the lights off.
Do you remember last night, Alfred? When we caught Joshua and his boys playing Pinch and Switch in my uncle's dirty washroom for almost an hour? I heard them giggling the whole time they were in there, but by the time they came out they were completely silent and stone-faced. I wish they had invited me, too...