Best definition
worm bag
when someone is fucking and just when they are gonna ejaculate, they pinch their dick and all of the cum

is still on the tip.
once u let go, it spills

my worm bag will spill any second, give me a cup.
worm bag: define #2
Wormbag
(n) Any human male with a collection of dilated blood vessels in his scrotum (see: varicocele, a condition which may interfere with fertility) who is otherwise extremely sexually and intellectually desirable.
I went out with that guy I met through Craiglist last night, turns out he’s a wormbag! Hopefully that means he’s never knocked anyone up.