Aaaaargh, dd(only 3.7 but still!) says this phrase all the time it has been picked up from dh, i try to ignore it when he says it because he is too old to change but really, who says 'i'm having a toilet' [rolls eyes]. She means she needs a wee, just for clarification
DH also has trouble with the use of bring/take which really irritates me too.
needed to get that off my chest
Apologies if anything is spelt wrongly of phrased incorrectly I'm not a fully fledged pedant