The same stuff is sometimes called the direct translation of "toilet water".
The usual modern meaning of "toilet" is of course one of those excretory euphemisms, like lavatory ("washing place"), bathroom, washroom, rest room, the French word cabinet (cupboard), little boys room, smallest room, loo, spend a penny, tinkle, wee-wee, pee (pee originally being P as an initial letter...) etc etc. My granny used to say "I'm just off to do something no-one else can do for me". And she could swear like a trooper.
We just can't bring ourselves to say those words out loud -- which AB won't let us use anyway.
The other French term pi*soire does have something to recommend it in directness.
Remember the wonderful Fungus the Bogeyman, by Raymond Briggs? (He also wrote & drew The Snowman, Father Christmas etc.) Fungus had many excellently disgusting things (such as Flaked Corns for breakfast) and his bathroom shelf had both "Eau du Colon" and "Toilet Water".