When a girl or guy that has a boyfriend/girlfriend and has sexual intercourse with another girl/guy, or when they don't have a boyfriend/girlfriend and they just have sexual intercourse with a person without a label.
"he's humpin and bumpin with someone else!"
":o"

"those people are humpin and bumpin"
"they're not even dating, though?
by 0001122 January 29, 2011
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