I am desperate for advice!!!

I have a 3 1/2 year old son. He’s been potty trained for over a year and mostly accident free. He still needs reminders but generally he’s very good about using the potty.

When he first started learning whenever he’d have a poo accident at night he would wipe the poo on his walls by his bed. It was disgusting but my pediatrician said it can be normal and luckily he seemed to grow out of it.

Now randomly if he poops in his pants he’ll shove his fingers into it. He’s not wiping it on anything or trying to hide it. When I ask him why he did it he says he was “putting it back in his butt”. I don’t understand why he does this. I try to be patient and make sure he’s praised heavily for pooping on the potty. When he has an accident I don’t make him feel horrible for it. I just clean it up.

He hates when I have to scrub his fingers after he’s touched his poop. And I usually take something away like dessert. I’d think these consequences would stop him but he still does it.

He’ll go months without having an accident at all then suddenly go a few days with touching his poop.

Last time he did it he ended up having a fever after those days of poo touching were done. He’s got a bit of a cold now so I wonder if he only does it now when he’s sick?

I have no clue and it’s driving me nuts.

Any advice or ideas please??