Night Jerker

The Night Jerker is an evil spirit who prowls about the world seeking the ruin of souls. Taking a particular interest in those seeking to free themselves from lustful habits, The Night Jerker sneaks in through open windows, cracks beneath the door, or really anywhere he can to seek to disturb their peace. One knows that he has been visited by the Night Jerker when he awakes to find that he has endured a nocturnal emission. It is possible to encounter the Night Jerker without such an unfortunate outcome, and one can note his presence by pervasive, sexual dreams. The Night Jerker is not to be spoken of by name, lest he take such utterances as an invite, but may instead be referred to as “The NJ”

Dude: Bro, the Night Jerker got me last night.
Bro: Woah I think you mean the NJ! Careful saying his name, he could be right behind us.