What is check your oil?

When a man is able to fold his penis back and stick it in to his own anus.

Have you ever heard of checking your own oil? I'm sure Ron Jeremy has done it quite a few times.

check your oil - video

I went to the doctor because my nards were sore and the SOB checked my oil.

When one inserts their finger in their own anus in order to gauge their personal stink level.

Don't touch me bro, you been checking your oil

When you run your finger across your bunghole in order to be certain that you wiped good enough.

I checked my oil and now I know how those stains got in my underwear.

When someone pisses you off enough that you threaten to stick something, like your foot, up their ass.

Dude, if you don't stop that shit, I'm going to check your oil.

Hey, let's go check his oil!