headwash Share definition Flag A blow job; to give oral sex to a man. This term was a popular 1980's slang. It is seing a resurgance along with other 80's terms such as dork and joystick. I caught a headwash from this girl I met at the bar the other night. headwash by toast455 July 1, 2005 0 0 Get merch Get the headwash mug. Buy Now — $32.95 See more merch