Definitions by Jimmy. Kimmel

Mammogram 

Occurs when the male sneaks up behind the female, wraps his arm around her, placing one forearm above her breasts and one forearm below her breasts. He them squeezes his forearms together, flattening the breasts.

I was over at my girlfriend's house for Thanksgiving when I gave her mother a hug from the rear squeezed her boobs with my forearms and yelled, "MAMMOGRAM!"

Mammogram by Jimmy. Kimmel November 29, 2013