If he has a j-pouch, then he doesn't have a rectum; the burning would be in his anal canal and/or around his anus.
But yes, this is normal. It's called "butt burn". Every body is built differently, so some get it more than others. It is usually easier to prevent than it is to treat. Typically the more frequently you go, the worse the butt burn. I get the same sensations on days when I go more frequently. Here are a few things to try if he hasn't already:
1) Diet experimentation - Keep a food journal to record everything you eat, and record when the frequency and butt burn are better or worse so you can figure out what foods trigger or worsen the situation. Adjust your diet accordingly. BRAT foods should help calm things down: banana, rice, applesauce, toast (or bread). Chocolate, caffeine, alcohol, and sugar all make it worse.
2) Try not to "push" or bear down when you go. I discovered that if I'm pushing too hard, I get that awful burning sensation inside my anal canal, which is difficult to reach for treatment with creams and such. I found if I keep the pushing to an absolute minimum, this helps greatly.
3) Water cleansing - Use either a bidet (people who own them swear by them) or a small squeeze bottle to rinse your bum with water after every time you go to the bathroom. Aside from the water being soothing, it's the stool/feces that causes the irritation, so if you don't clean the area completely, it will continue irritating. It also reduces the need for wiping with TP, which irritates the area further. Baby wipes also work much better and are easier on the bum than regular TP. (Great for going "on the go" - I keep a ziplock of wipes in my purse at all times.)
4) Creams & Ointments - Calmoseptine is the most common for butt burn (see link at top of screen), but there are many others out there. Some are specifically designed for adults with butt burn (B-Sure Bottom Balm), but I have heard that regular diaper cream works as well. I use A&D Ointment and/or Aquaphor. I also keep a chapstick-sized tube of Aquaphor in my purse at all times.
5) If things are really bad, and you are in an emergency pain/burn/itch situation and just need some immediate relief... Hop in the shower and take a finger-swipe of Noxema (face cleansing cream that comes in a blue tub), smear it down there right in between the butt cheeks, and leave it there for a few minutes (or for the rest of your shower). It might sting a tiny bit at first if you have any raw areas, but after a minute you will feel an intense cooling/soothing sensation, and it will also clean the area really well. Rinse off before you get out.
Let us know which of these he's doing already, and which ones seem to help. Hopefully the skin around his anus will start to adjust and become accustomed to the higher frequency, and it will be less of a problem... I think in most people that happens within the first few months, but maybe his body is just taking longer to adapt. Good luck, and keep us posted.
