gag-factor
A scale from 1 to 20 that tells you how much a guy’s junk is being sucked. 1 is like a kid sipping soda, 20 is like a guy’s junk is being sucked so hard it could kill a man.
My brother got a 20 on his first blow job and he fainted.
My friend’s girlfriend gave him a 15 and he started crying.
My teacher said my gag-factor was 12 and I got a D.