I was in the bath when my stepdaughter walked in on me while I was masturbating. She quickly sat down on the toilet without caring that I had an erection and the sight of her naked bum on the toilet was a huge turn on. She blasted out a huge load of diarrhoea into the toilet while I held my penis and while she sat there waiting for the next wave I came all over my hand and chest. She did some more wet diarrhoea and then wiped and flushed the toilet.