Communal peeing: a new mode of flood control in ants

[Jonathon Green]

Speaking as a Brit, I would suggest that 'pee' has yet to make it as
'formal' English, although it's a few degrees more likely to become so than
'piss' (for which it is, after all, a euphemistic abbreviation), for all
that for a good many centuries, up till the 18th in fact, piss was accepted
as standard English. Pee, as noted, is colloquial, and often juvenile. Like
'willie', which in the last couple of decades has become the (middle-class)
mot juste for penis, it does seem to have wide popular currency, but
'formal' remains another story.

Jonathon Green