The male reproductive organ. A penis. Protein shooter. The dangly thing between your legs other than your balls.
"Dude she totally wants my girth worm."
"my girth worm is shriveled."
"who put dirt on my girth worm?"
"my girth worm got scared when i saw her gunt."
"the early girth worm gets the bird"
"my girth worm looks like your mom."
An incredibly thick penis. Because of the extreme thickness, there are no condoms that can contain this massively wide unit. In order to have intercourse, one must wiggle their dick like a worm for several minutes to burrow in even the loosest of vaginas.