look up any word, like cunt:
 
1.
The act of intercourse. Similar to tubthumping, banging, and floozing.
Did you see those three dogs stuck together? That's some pretty crazy coitis.
by J. Warner May 08, 2008
 
2.
The act I have performed on your mother in the previous nights.
He must be very skilled at coitis.
by Sheldon L. Cooper July 25, 2014