a) The act of hooking up; action; ass.
b) The act of cumming, usually male.
a) Steven: Yo, do you actually like this girl?
Joe: Nah, bro, just trying to get some chupi, Birmingham Booty Call style.
b) Rami: Yeah, and to make matters worse, her mom walked in just as I was about to chupi on her daughter's face.
c) Victor: The doctors pumped her stomach expecting to find liquor. Instead, they found about a liter of chupi. She was pretty industrious, apparently.