A super big cock with a huge circumference, used to pound pussy. It is usually associated with a Pete North sized load that spews out onto a woman's face.
Sean: Dude, I just don't know how you do it. You're always slamming box.
Sam: Yea, well when you have girthzilla pipe like me, you can do whatever you want and girls will be pulling their pussies out all the time and begging to give you bobbles and the ole fashioned hand jobs.