masturbate. The "one" is an orgasm, i.e. rubbing one's genitals to the point of climax. May also refer to a handjob or fingerbang, or more generally, any manual manipulation of genitals.
I got so excited watching her video that I had to rub one out.
Rub one out meaning literally what it means, a women/girl rubbing their clit/fingering vagina until orgasm. A girl flicking the bean meaning rubbing her clit until she explodes her load.
She was looking at a man’s naked magazine she got so horny she had to rub one out
The act of male masterbation and orgasm prior to going on a date where it is apparent he will score. The male performs this act up to an hour prior to the date in order to facilitate a longer lasting erection (thus satisfying her every need later on)
Bill knew Sally wanted to bone that night, so he rubbed one out in the bathroom before he left to pick her up for dinner