I just got one question and I'm sorry if it sounds disrespectful, but: If you know ahead you are not comfortable/good at writing m-rated scenes ( in your case) then why start off an m-rated story? The best advice would be not to start them and try non m-rated stories first and practice your on the side with prompts or one shots. This is really the best way to go about it. Do proper research when it comes down to writing and don't go by what other AFF-ers write, because sometimes the on this website is THE most unrealistic ever.