When a guy ties a string around his nuts and puts the other end of the string in the girls vagina. She then reverse digest the string and then poops the end of the string out. the guy then takes the pooped out string and pulls hard (still having the string attached to his nuts) popping his nuts into the girl. "Pop a Nut"
Whoa shit man, i popped a nut, or "Pop A Nut" in your girlfriend
last night, i really hope your not mad.