Top definition
When in a threesome, the act of a man's testicles slapping against the forehead of a third member located beneath the man's partner.
Roger: Gladys, why is your forehead so sweaty?
Gladys: Man, Frédéric just gave me Indian Hacky-Sack with Joanne. It was ball-slapping fun!
Gladys: Man, Frédéric just gave me Indian Hacky-Sack with Joanne. It was ball-slapping fun!
by Funny Boner December 12, 2015