What if they told you they’d done a shit?
it’s funny, really, kids know/learn what language is appropriate to use when, just like adults. they may say stuff at home they would never say around a grandparent or at school/nursery.
if you say ‘I’m going for a shit’ then so will your kids – they just reflect your modelled behaviour.
My son brought that home when, at 2 and half, he called his mother a f*cking w*nker, at volume, in the queue at Homebase ‘cos she wouldn’t buy him some chocolate. She moderated her language whilst driving after that.