Yes and there's photographic proof, ha
When I was like 4-5-ish my family took a picture of me when I was done. I'm not sure if they knew I was masturbating, though. I kind of like it--- it's like photographic proof that my fantasies were legitimate back then; I can remember that moment super clearly--- what led to the masturbation session, the after, etc.
I think I might have stolen the picture back from them, but I'm not sure