We I am in childcare, so we are taught to use the correct words - though for me this is difficult as not all parents are in agreement and you have to follow the parents wishes.

One example though - A 3 year old girl was in the toilet with her pants off and doing a 3 year old dance around the basins! Anyway she's patting herself as she sings 'bum, bum, bum' but she is actually patting her vagina - so I said no sweetie, your bottom is at the back and she asked me what that was called, so I told her, your vagina - she was happy with that information and eventually got dressed and returned to the group.
Not sure what her parents might have thought if she went home and told them what it was - but I didn't get any complaints!