Last October, I purchased my first trailer my Little Guy Max aka The T.A.R.D.I.S. On one short trip my friend sat on the toilet and then realized the bowl was leaking into the shower-pan. It only leaks when someone has trouble distributing their weight. Any ideas? I put a stool in the shower (no joke) so it could be used very carefully (I'm very short.) This does not entirely stop the issue if one shifts their weight mid-use. Please advise.