1 definition by ThreeGee

The act of having sex with three generations of a family. Hence, 3G. Three Generations.

This act can be performed as a foursome, threesome, individually or even as a combination. The 3G is an event only the smoothest of men/women can achieve.
See: milf, gilf, dilf and gdilf.
In conversation:
Dan: "Dude, what'd you get up to last night"

Sam: "Finally completed the 3G with my girl's gran!"

Dan: *crowns the absolute legend*
by ThreeGee April 25, 2016
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