When a chick comes up behind you, clothed or unclothed, and her boobs rest over your shoulders and around your neck resembling an emergency life-vest.
While trapped in a cave, Grant stayed alive by falling asleep in the security and warmth of his best friend's lifejacket; even though it was a little gay.
by cowtipn January 23, 2007
A protective device that you put on before you Motorboat a woman with ample cans. Also a visual aid to display your intent to said woman.
Ben, bored with two cats in the bath tub, buckled up his life jacket and dove into a hearty set of knockers head first.
by thed00d! October 11, 2008