An erection that occurs every time you are exposed to a certain, seemingly unrelated stimulus.
For instance, getting an erection every time you see a hot chick is not a pavlov's dong, but getting an erection every time you see a trumpet would be.
Pavlov's dong is usually caused by association. If you had this really hot girlfriend who loved donuts and she broke up with you, the association of your old girlfriend is what would cause a pavlov's dong with donuts.
"Dude, you're in a room full of guys and you just got a boner."
"No homo man, it's just a pavlov's dong."
Mannerism Bingo is a game played by students on a boring day of class. It is played by creating a 5 by 5 game board in the style of bingo, but putting a bunch of the teacher's mannerisms in the boxes, playing until one person has any row, column, or diagonal completely crossed out.
Like the normal game of Bingo, rules vary from place to place, but there are 2 central rules to mannerism bingo which are constant. One, if one achieves Bingo, they must somehow say it out loud so that the rest of the class can hear without getting in trouble for being distruptive (a common strategy is to raise your hand and try to work the word bingo into your sentance). Two, the teacher in question must never, ever discover the existance of mannerism bingo, or it is totally ruined.
Mannerism Bingo is very strange in that high school and college students all over the world claim to be the ones who invented the game, yet no one actually knows where it came from. Earliest documented games of Mannerism Bingo are from around 2004, beyond this no one knows.
"Mr. Johnson, do you think they had the game of bingo in the 1600's?"
"That was a great period for mannerism bingo, our teacher was filling in so many squares for us."