OMG - someone else who has this problem. My son did something similar around the puberty timeframe. For him, the problem was partially constipation and mostly not getting up to go potty until too late. He was so focused on what he was doing that he didn't register the need to to potty. We put him on a potty schedule (go when you get home from school, go every 2 hours, go at bedtime)until he figured out his body signals. We treated the constipation with Miralax. Also, have flushable wet wipes available at all toilets in the home. They work better to thoroughly clean the backside, and since this is probably a sensory issue, he may find this makes him feel clean instead of taking baths. Best of luck to you - I'm betting this will pass as he gets older.

Well my son enjoys doing this. I asked him why does he do it and he says that it feels good. He has a special place that he does which is in his bedroom in his closet so now we locks him out of the room. I really don't think he is constipated because he doesn't have a problem doing its another type of enjoyment which is connected with puberty and/or sensory issues. I spoke with his OT about it being that she is suppose to talk to me about it but she haven't got back with me yet. This is very frustrating.

My son is only 4 so maybe I am not in the position to answer your question yet. But just want to share some thoughts: I think it is sensory issue, my son refused to sit on toilet when we first started the potty training, later I noticed that it is the touch on the skin that he does not like. So I rub his leg and butt EVERYDAY, whenever I have chance, just to make his skin there less sensitive to touch. After a few months he could sit thru. I know a 12 or 13 years old may not let you rub his leg that often, but maybe it is easier when he barely wakes up in the morning, this is how I started. He thought I was just cuddling with him...

I had the same issues. It got better with time. Thats not helpful i know but it may give you some hope. My son started to improve around age 15.

:(
My son is 13. He has severe toileting issues. Also just with bm. He can urinate just fine. My son's issues are.. i'm just not even sure entirely. He just WON'T sit in there. If i make him sit on the toilet; he wont' do it there. he'll wait until he's having quiet time in his room. then he'll do it and sneak into the bathroom to dump it in the toilet. he obviously understands that it goes -in the toilet- and not his underwear. i've done everything under the sun, but the teacher/staff at his school love to treat me like I'm just some neglegent parent who refuses to teach him how to use the toilet.
When/if it's a sensory issue, then it's a really hard situation to address. you can have all the scheduline, structure, and visual aides in the world. Unless the child themselves are willing to do it; and at this age... it does have a lot to do with them being willing. but i do think it has something to do with sensory issues.