Hi Ruby
If you were to put a nappy on your DS in the day would he poo in it?
DD is almost 5 and would only poo in a nappy until about 8 months ago, she was scared that pooing on the loo would hurt. We tried everything, sat her on the loo reading her stories, singing songs pretending to blow bubbles (apparently the bubble blowing thing helps them to push down for a poo), but nothing worked, she would get upset me and DH would get upset and it was so stressful.
I called the HV for advice and she said not to worry as it's really common and that putting a nappy on DD was fine. So what we did was this, DD would tell us she needed a poo, we would put a nappy on but would tell her that she had to go to the bathroom and do it in private, this was a bit of a battle but after a few weeks she did it without fuss.
Once she felt at ease with going into the bathroom we then told her that she could have a nappy but she had to sit on the loo to poo, again it was a battle and we had a few tears and tantrums but she got it in the end.
When I was confident that she was comfortable with sitting on the loo I played a little trick on her, she said she needed a poo one night before bed so I put a nappy on but what she didn't know was that I'd cut a hole in the nappy so when she poo'd it went down the loo.
She was amazed and she was a bit cross with me for playing a trick on her but it paid off and we've never looked back.
I know how upsetting and frustrating it is, but try not to worry, It's only since speaking to other mums that i've realised just how common it is.
Good luck:)