Ask him to get his own towels and clean up after himself.

send him to counciling

Seek professional advice.

What is wrong with masturbating???? 1 in 3 people do it! but I do agree with other people he should have his own towels or even wear condoms.

This site has really become a cesspool...when I joined 3 years ago intelligent people posted intelligent answers to serious questions. This is a serious question...this person is asking for advice. Each answer here is utter crap. Do you people even read the question? Do you know what subject matter it is pertaining to? I don't think people understand what Autism is, which is why you're getting these idiotic answers. People with autism, even if they are high functioning, can develop compulsive, destructive habits. Compulsive masturbation is definitely something than can develop, and should be addressed immediately. If he is ejaculating up to 8 times a day (if only we all had such stamina), he can develop very serious prostate problems at a young age (of course i'm only assuming he's young from how you describe). The simplest solution may be to actually sit him down and talk to him...if you are comfortable as a man speaking to him about masturbation when he isn't your son, by all means try it. He may listen, but then again he may not. As you say, you have talked to him about it but he doesn't want to stop. Counciling may be in order, or methods of punishment. Autistic kids in my experience tend to respond to punishment or threat of punishment more than anything else. It is especially disgusting if he is ejaculating into your towels and bed sheets. The other answers here simply say "tell him to use his own towels" or "there's nothing wrong with masturbation". Clearly, these people don't have a clue about this subject matter, and their postings should be ignored. This is an extremely serious problem that may require professional intervention. Autistic people are incredibly difficult to reason with if they have emotional or compulsive extremes. I myself had an ex girlfriend that has a severely autistic brother. Aside from compulsive masturbation habits that icnluded masturbation in public places, school, and (ugh) at the dinner table, he would often times fly into fits of brutal rage, and viciously attack anyone in sight, including his sister. Once, he tackled her to the ground and punched her repeatedly in the face, shattering her nose. I wasn't able to stop him until, sadly, I had to kick him square in the face, knocking him unconscious for nearly 10 minutes. When he came to, he immediately flew into another rage and tried to attack us again. He kicked a locked bedroom door down, screaming like a maniac, wielding a kitchen chair as a weapon. After taking a brutal hit myself, I once again had to subdue him by physical retaliation. After being committed for several months, he came home on new medication. When he went back to school in the fall, on the first day he beat a 16 year old girl to within an inch of her life, completely unprovoked. To my knowledge the girl is on life support to this day. As much as I loved my ex I could no longer be involved with her after that. I occasionally speak to her from time to time and I have learned that her brother has been in an insane asylum for nearly 3 years, in a solitary confinement. It is possible he has other forms of mental illness, but doctors who examined him found no traces of any other mental difficiency, except for severe autism. People don't seem to realize how serious of an epidemic autism is...some sources predict that 1 in 5 kids will be born with a varying degree of autism by 2020, and that 1 in 3 of those children born will be "severe" as in incapable of function and quality life.