Brought up by my widowed mum, I was 18 when I learned that men don't sit down to pee. I'd got a job as a cleaner in the pub and was confused by the urinals. The landlady was in stitches when I asked what they were.
Me: Any discourse that advances for a single acceptable way for men to wee, presupposes that all men have one (or one of a few) urethra path(s) that intersect with gravity in particular ways. This is inherently normative and exclusionary to intersex men AND transphobic, regardless of whether the speaker is demanding sitting or standing. Wendy's employee: Sir, I'm still going to have to ask you to stop doing handstands on the cistern. Me: _CIS_tern, is it?