help with recurrent cystitis??

I've been noticing recently that I've been getting cytitisis about once a month and while I don't get it severely, it is abit of a pain for a few days. I'm still a virgin but I do masturbate sometimes and I wondered if you need to pee after masturbating like you need to after sex? I also wondered could my shower gel be too irritating for my intimate area - should I be using a feminine wash (just externally, not to douche) instead?? Any other tips on preventing cystitis would be great!