When you try to get the last drop out of a pop can, but it won't come out. You have a "null" face as you look like a "chup", or a shmuck, trying to get the last drop out. Origin "chup-null-gator", someone trying to get the last drop of gatorade, but instead got a chup-null.
by Chup-Null-Gator February 22, 2008