Analog perving
Back in my student days in the 80s, a mate and his girlfriend had a bedsit where they shared a common bathroom with about 5 other bedsits. We were round there late one night smoking (but naturally not inhaling) when the GF came back from the toilet looking rather pale. "There's a bloke in the bathroom cupboard" she said. Boyfriend legged it to the toilet to find the cupboard door open, but no bloke. There was however a hole drilled in the hardboard cupboard wall, pointing right at the toilet.
Turns out she was sitting on the bog, heard a scraping noise, and the cupboard door swung open to reveal a guy squatting in the rather cramped space. This is 2am, but unbelievable as it seems now, he muttered something about "plumbing", at which point she made a hasty and undignified exit. He must've sat in there for an age just waiting for someone to come in; if it was women he wanted to see, he really would have been in there as I think she was the only one in the building.
She recognised him as from one of the rooms on the lower floor. His door was duly knocked, but he'd evidently decided to go for an expedient walk. We were very averse to the Filth at the time, so she didn't call them and that was kind of that - except she now checked the cupboard every time she had a bath or a crap and dried her smalls in her room.
He did however get his desserts in the end. His room was in the front of the house and had a large window with no net curtains. He evidently decided to have a mid afternoon wank while sitting on the floor, in clear view of a flat in the house opposite - which just happened to be tenanted by two female coppers. It may have been pre sex offenders register, but the local rag ran it's own line in "name and shame" when reporting local court cases with seriously cheesy headlines. In this case, something like: "Flasher exposed by WPCs given suspended sentence".