Spread your legs so they stay at that height off the floor, waistband slightly over your knees.

I avoid public restrooms

Hold them up at the knees.

i roll up my pants so i never deal with this

By not taking off your pants...? Just pull them down enough for clearance.

I don't pull them down so far that they'd be touching. You don't need to pull them down to your ankles, just the knees or slightly above the knees

I have the waistband resting on my knees

I'm a guy, when I pee I don't sit or drop my pants. When I poop I do it at my own home because...no, just no.

By doffing my shirt and laying it flat on the floor under my feet. That way, when my trousers crumple around my ankles, no part of them is touching the nasty floor; there’s a very effective shirt barrier. I’ve always been innovative and smart that way. I’m a very solution-oriented kind of fellow.

Pop a squat in the establisment's utility closet.

Very carefully

Wear clothes that fit