prejack
The act of masturbation (but not to full orgasm) such that any further stimulation will result in an instant ejaculation. A cock in this state is now considered to be prejacked. Contrast this with a limp dick or a fresh boner where it needs a certain amount of stimulation prior to ejaculation
DALE: Hey Minday, wanna fuck?
MINDY: I would, but Katie told me you prematurely ejaculate
DALE: Ohhh no fuck babe, I just prejacked myself sometimes