My housmate is straight and although he has a gf, it is not unknown to have other girls back to the house, (while she is working away mostly). I have been into the bathroom and found used condoms , sometimes just left on the side . I did say he needed to put them in the waste bin, and i think he was a bit embarrassed. The bin in his room is often full of cum tissues or condoms. He had trouble with his laptop one day and he asked me to fix it, as he is useless at such things) and half way through , he decided he was of little use and would go and get some milk. While he was out, i looked through his browsing history at all the porn websites he was looking at, and then found a pic of him which he had sent to one of the girls he had picked up, with him nude with a hard on. I have to say, the USB stick came in handy that day!