When you get
excessive joy over your own post on Facebook. I've "posterbated" in a way, I suppose, by using joint-posts (posting two characters in one post) or by having multiple characters in a thread (in a case in which they would have to interact), but that's not deceiving or even done for my own
entertainment. I do that because it's
necessary for the scene/plot/etc. Because I'm both a writer outside of roleplaying and an avid roleplayer, I don't find it to be difficult at all to write my own characters' interactions with each other.