Put pants that he can't take off to touch it and but my son used to do this when he was younger and I would just do that ... Last year he started doing it again but I would try and make him understand you don't touch and remove his hand

I do catch him every now and then rubbing something on it but once I remove it he won't do it again it's like every few months

He also has ASD he's 6

My son is a typical boy and is always grabbing around for his wiener. I just tell him it’s a private area for a private time and try to redirect. I know your son is on the spectrum but I honestly think this is normal for boys so you should find an age appropriate way to explain touching and private time to him. When you notice him doing it, ask him to go to his room. We don’t want to scare them from exploring themselves. Just want to reiterate a time and a place.