person 1 says: hey your tank is empty, maybe you should fill er up  person 2 hears: <mumble> fill er up
the term used to tell someone that they should deposit some more petrol in the tank of thier car if you are drugged to the eyballs
"person 1 says: hey your tank is empty, maybe you should fill er up  person 2 hears: <mumble> fill er up" What is the definition of "fill er up"?