To get it started I live with my son in our condo. He has just turned 18 years old.
I work at a beauty salon so I always have tons of skin and hair care product laying around. Well the other day I walked in on him in the bathroom using one of my bottles of lotion to masturbate. The opening was big enough for him to fit his thing in it and was basically having sex with it. He was so embarrassed about it that he almost fell trying to cover up.
After he calmed down I told him it was ok and asked him how long he had been doing it and he told me a few weeks now. Well after he went into his bedroom I actually looked at what cream bottle he was using and was horrified to notice that it was my face cream I used every night before bed. With the fear of not actually wanting to notice the answer I just had to ask him if he had been ejaculating into the bottle. To my horror he told me that he has been. He said he thought it was just an old bottle that's why it was kept in the bottom of the closet. Little did he know I only kept it there because the bottle was too big for the cabinet and too ugly to leave sitting out.
I was so disgusted by it I didn't even know what to say, he just asked me innocently and scared if I actually used the lotion and I was honest with him and told him that I did often. The look of complete disappointment came across his face and just told me how sorry he was. He just asked me how I didn't notice. He said very shyly that he had probably did it in there like 30 times or so.
In the end I just talked to him about sex and masturbation and where and when he should do it all. At first I was so entirely disgusted about basically rubbing semen on my face every night but have figured that he didn't mean it in a destructive way so I have no reason to be mad at him. Since then I have noticed that he has been using towels and such, which I'm still not happy about but it's better I guess.