If Ren tried to wash lower than the small of Farfarello's back, Farfarello would probably try to hurt him--they were quite in agreement on the issue of boundaries. "The nurses are realistic. The rest of this place isn't." And Farfarello would know, being an institutional veteran.

Farfarello extended his left arm, glancing back at Ren. "Get the arm, too?" Please wasn't really in Farfarello's vocabulary, unless it was in a sarcastic sense, but at least he was phrasing it as a question/request rather than a demand; for Farfarello, this was excellent behaviour indeed.