S.V.
My oldest was a famous tub even shower pooper till about 2-3. Yes it does relax them as gross as it was I didn't mind so much because he always had issues with pooping. It does relax them. His doctor actually made that suggestion to me to use a warm shower or bath when he was really constipated when he was still an infant. Now that he is five there are still times he will get in for a few minutes and we have to get him out so he can use the toilet. Its not uncommon.