Sacagawea
The act of placing your scrotum (the "sac" in Sacagawea) into someone elses drink. This is done in plain sight of others, so that when the person returns and takes a drink, everyone can yell: "Sacagawea!" After which much mirth and hilarity ensues.

If the victim is a guy, then it's considered male bonding, and his ability to laugh it off is part of "taking one for the team", and showing that he's part of the crowd. (If he then takes a second drink after discovering the prank, then he's attempting to bond a little too much.)

If the victim is an unattractive woman, then it's the equivalent of a pity fuck, and she is expected to display much gratitude.

If the victim is an attractive woman, then she's been given the high honor of being allowed to act disgusted in front of everyone to maintain the illusion of her virtue, while silently climaxing at the thought of what she has just ingested. In return for this opportunity, she is obligated to have sex with the perpetrator.

Crowd yells: "Sacagawea!"

Male victim: "Damn! (laughing) At least I know where you sleep!"
Unattractive female victim: "Delicious! I knew I eventually get a chance to taste you!"
Attractive female victim: "That's disgusting! I'm leaving! (then whispers) 555-1234"
