Well, the simple and most effective measure is to just tell them in an osay to stop. If they don't, then you can report it to the imms. That's when it becomes harassment really... well, sure, icly it can be harassment, but if you don't say you don't want to roleplay that, then... uh... well, I don't think they can do -too- much about it, unless it goes right over the cliff and down seven layers of hell.
Like fuzz butt said, tell them you don't wanna RP that. You have to do it in an osay, cause... icly... even Daklore wouldn't really listen. ... And Daklore doesn't even feel the Lx6+1 up! ... Hrm... naw, it's not worth having my hands diced.