In my new bathroom.
They look tatty after a few days, are essentially a sponge of piss and they stink like the gent's urinals. I've told DH I don't want one and he looked at me like I'd just told him that we're definitely going to have to start shitting on the dining table.
Disclaimer: the floor on our bathroom is now wipeable, so I can easily disinfect in every day if need be.
AIBU to not want a piss mat?