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(greh-shum-ing) Verb: The Act of having any sort of sexual relation on or inside any school property.

Derived in 2011 by a Bakersfield, CA news story involving several brothers, with the last name of "Gresham" being expelled from KHSD for making whoopie on a school campus, with other girls.
Guy: Hey whats up babe?
Girl: Nothin, you wanna have some fun after 2nd period?
Guy: You thinkin what i'm thinkin?
Girl: Get ready to start greshaming babe
Guy: Oh Yeah.!!
by TheKopp08 October 24, 2011