The process of excreating (taking a shit) and ejaculating at the same time. Hence, havin' a roni.
"Do you know what it's like, havin' a roni?"

First used on the 1989 song "Havin' A Roni" on Vanilla Ice's debut album "Hooked". Also on "To The Extreme"
by Sir Psycho Sexy May 16, 2006
Get the havin' a roni mug.
to have a dance party, or a bunch of people gettin smashed
"dude their havin a roni and Nunca Duerma is playing!"
by dizzletron March 14, 2010
Get the havin a roni mug.