We just used penis always! In the bath, wash your arms, legs, penis etc at first when we were doing it & then no he does it we remind him where to clean. If he was playing with it even as a baby we'd say something about it. Now with Juliette he is getting a bit confused & calling it a bottom, but we tell him no this is her bottom & this is her vagina. He got muddled though & though the bit above it was the vagina & told me the other day "this is my gina mummy" pointing to the bit just above his penis LOL! I think we need a bit more practise on that one