Easily the lowest point in our recent history <| sep |> How much is he doing it ? It ' s always worth ruling out something medical , or even something as benign as nappy rash or sensory issues from underwear . I wouldn ' t stop him doing it but I would redirect him to a private place you can use visuals to help support the idea of private and public and use them when you redirect him . He will likely grow out of it but a number of the autistic childrenteens I worked with mostly with intellectual disability were still rubbinggrinding in public . It ' s much harder to teach publicprivate once they ' ve been allowed to rub and grind in public until their teen years so it doesn ' t hurt to start now . Just make sure to do it in a way that he doesn ' t think he ' s been bad .