Bio break, relieving yourself, whatever you want to call it.
Is it bad to hold your pee? – Heba Shaheed – YouTube TLDR: It can be.
Instead of asking if someone needs to use the bathroom, try asking if they can try to empty their bladders (hint – your kidneys are always working, so the answer will always be that there was at least something in their bladder, even if they weren’t feeling the urge to go).
Good explanations of why you should empty your bladder now instead of later? This bathroom is much nicer than the one at <location> or we’ll be traveling and stopping to find one later will be hard or might make you miss out on part of <activities>.
After using the toilet, make sure to wash your hands!