Blow-off valve 

In a car that is equipped with some sort of forced induction system ,such as a turbo or a supercharger, a blow-off valve is usually availible as an aftermarket part to release excess pressure (boost) from the turbine system. Makes a very distinct noise. Like - pssssshhhhhhhhh! Or somtimes a chirping noise depending on the blow-off valve. Usually replaces a stock part usually refered to as a by-pass valve.

1. Gil: Whoah, dude! Did you hear that car go by?
Willy: Yeah, it sounded like it had a blow-off valve.

Blow-off valve by Wilburt May 9, 2006

Car girl Blow Off Valve 

The act of fucking a car thot and while she climax’s pulling out so she lets out a couple of loud, wet, queef’s

car thot: I really need a good guy in my life.
Thot destroyer: well maybe if every guy standing here hadn’t given you the Car girl Blow Off Valve you could find one

Car girl Blow Off Valve by The car guy brad May 9, 2019

blow some carbon off the valves 

When one finally has sex after an extended period of abstinence. Sexual intercourse is compared to starting an engine that has been sitting for a while and has accumulated excessive carbon deposits in its inner workings.

Dude, the last time I got laid was during the Cretaceous Period, I've gotta blow some carbon off the valves .

blow some carbon off the valves by Spency McGee September 20, 2017