Where is that cop peeing? The car door?

I don't get it.

Why is that fat cop always peeing, and why is he seemingly peeing on the cop car door instead of .. I don't know, ANYWHERE else? I'd hate to think what it would smell like or feel like when he closes the door right after the deed, and the pee splashes all over him (of course the actor wasn't REALLY peeing, so this doesn't visibly happen, but still).

I mean, it looks suspicious and weird when he does it first during the night/evening, but then the next time we see him, he is doing it AGAIN, so this really requires some kind of explanation!

Do cops keep some kind of 'pee jar' in the door? Is there some kind of accepted peeing custom I don't know about that cops did in 1977?

This is so puzzling - not that anything in this movie makes any sense, from the money (the pile of hundreds is WAY too small for 'fast car + 400 cases of beer' - the pile of cash should have been thick as a log - AT LEAST) to how they 'paid' for the beer (they really didn't - breaking and entering is not lawful even if you leave a nonsensical scribbling on the ground) to the lack of consequences (they would DEFINITELY have been caught at some point, it would've been a 'manhunt' of sorts) to how someone with options would choose a constantly shrieking and yammering, ugly naghag that treats him like a slave from the moment they meet to the end - getting some 'beaver' is not worth all that), to the bad dog handling, etc. etc.

Does anyone have any information about the 'peeing on the door' bit?