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