1 definition by THAT1GUYFUCKINurmomW
To ejaculate while slapping someone in the face with ur dick. Commonly used when black people are fighting over koolaid or other commonly used black stuff.
'I was fuckin this chick when i was at bj bell and then my friend yelled at me so i gack slapped his koolaid.'(gack slapped while koolaid is involved.)
by THAT1GUYFUCKINurmomW April 25, 2010