The actual fingers on the keyboard part, not so much. There's still an energy, but it's more creative than horny. However, I don't usually get to that point if I haven't first been fantasizing about a situation for some time and have probably masturbated to it a few times before setting a single word down of a story. Also, as a writer, I also get turned on by the thought of others reading my work and becoming aroused. Knowing that something I've produced has had that effect on someone else is really exciting, and probably one of the biggest reasons I continue submitting to the site.