A common phrase said in the time period between ordering pizza and receiving it. After bonging some salvia and smoking some jays and everyone has bare munchies, pizza is either ordered by phone or direct from the shop. The exact rules on "shotgun" are not clear, but any-time in-between ordering and getting the pizza, one may say "Shotgun the dip" and therefore they have ownership of the dip on #1 the pizza they ordered to share OR #2 a random persons pizza (method used by stingy persons) and no one can questions this.
Person1: Yay, the pizza has arrived
Person2: Shotgun not hoisting
Person1: Dam.... SHOTGUN THE DIP