Pain urinating after pelvis radiation

Ive heard there isnt much you can do for the pain. But ive noticed alot of people talking about pouring warm water on their vagina while they urinate and that it helps alot. Im justt curious exactly how to do it. Do you get in the tub or just sit on the toliet? Ive been doing everything I can to avoid urinating for the past 2 days. I know its not good to do that but this pain cant be good either. I never thought id be scared to pee, lol. Someone please help me. Im a single mom of an autistic 17 year old. We moved in with my parents but I feel so alone after find’n out I had cancer. Im embarrassed to ask queations or talk about certain things to the drs and even my mother.