The act of holding in a juicy fart while in public, only to sneeze, causing you to involuntarily rip a noisy grumpy at the same time. Usually followed by desperate seat-shuffling or forced awkward conversation in an attempt to conceal embarrassment.
Professor: And so the hypotenuse is equal to the square of . . .
Jim: (Oh God, not now. Why did I eat so many burritos?)
Jack: Dude . . . You alright?
Jim: Ah-CHOO! (flatulates simultaneously) COSINE IS SQUARE ROOTED!!
(Professor squints over his glasses with a puzzled expression. Rest of class stares awkwardly.)
Jack: (sniffs) Dude . . . Did you Hi-Low Blow?
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