Teaching them what's right and wrong is difficult

My son is 16 and has ASD, BESD and learning difficulties, what we're finding is now he's going through puberty he doesn't seem to see anything wrong with showing me or his dad his private parts, we've tried explaining that it's not wrong and he should do it upstairs in his room. I'm not so sure he really understands. Another thing is he seems to have a thing for poking me in the ***, I've tried to stay out of his personal space but that doesn't always work. Does anyone have the same issues once they go through puberty?