Boner Fairy
A little wiener shaped creature with wings that fly's through the night and gives people random erections while they sleep. Due to high volume of night time boners, the Boner Fairy is said to be quick a swift with her work, and seldom is spotted, and never is caught.
"Dude, I ripped a hole through my whities and my Egyptian cotton sheets. Boner Fairy must of paid a visit last night.