wtf is a schrader valve?
 

ive been searching and only found references to it, like hold it open or remove it. so where is it?

a spring loaded valve used to hold pressure inside of a closed system (tire, A/C etc.)

what he said^^^^ what ur thinking of is most likely on a tire.

http://encyclopedia.thefreedictionar...Schrader+valve

what part of the car are you working on?

im checking the compression
and it looks like if there is just a valve you hold open that'd be easier than pulling plugs ect

Ah, what that means is that if your compression tester has a little button you push down to release the pressure, you can use that. If not, at the hose side of it, you can use unscrew the schrader valve, They make tools for the tire ones, but you can use a small pair of needle nose pliers if you're careful (and your valve is compatible). It should just screw out.