Mammary intercourse

A couple engaged in mammary intercourse. Left: An illustration by Seedfeeder of the woman in a lying position with the man ejaculating, Right: An illustration by Thomas Rowlandson of the woman in a (semi)-sitting position

Mammary intercourse is a sex act, performed as either foreplay or as non-penetrative sex, that involves the stimulation of a man's penis by a woman's breasts and vice versa.^[1] It involves placing the penis between a woman's breasts and moving the penis up and down to simulate sexual penetration and to create sexual pleasure.