For bottom irritation due to radiation and diarrhea, which is best for a sitz bath, warm or cool water?

Warm to slightly hot helped me - also had a bidet installed into my toilet.

I got a bidet attachment on Amazon that I found on here, it was around $30 from amazon and was worth its weight in gold!  Highly recommend.

If it is a radiation burn, I tried warm water. That didn't work. The prescription cream also didn't work. So I tried bag balm and it was the best decision I ever made.

Cool worked best for me. Warm only made it worse.