When the group of RPers I am with moved to this site, the first thing we did was get a clarification on the rules. I wouldn't consider myself an erotica writer, but the way i've always approached this shit is with the assumption that saying I am uncomfortable writing something is saying I am weak or incompetent somehow, so I do like the ability to practice writing whatever type of scene I think fits best in any given situation.

Anyway, like I said, we made sure to get mod clarification before we all joined the Guild, and according to Lilian Thorne, the most important thing to avoid is stringing together overtly-sexual buzzwords. You theoretically could write anything so long as you were delicate with the language. So that is how i've been approaching the subject ever since. 

In regards to smut vs tasteful vs fade to black, I think each has its own place. Its like violence. Sometimes an over-descriptive violent scene is preferred, sometimes a tamer version is better, and sometimes it is better to mention 'off-stage' so to speak. If you are RPing about something violent, like gangs or war, than avoiding violence all together might come off as cheap. Similarly, if you are RPing about relationships and avoid sexuality all together, it can very easily look goofy.