when you dont jerk it off for a long time and it cums in sleep
When you ignore your penis, don't fap for a long time, it gets angry and cums in sleeps, also known as wet dream.
Jack: Aww man!
Bob: What??
Jack: I was sleeping in bed, having a dream about the autistic kid at our school making a fool of himself. And suddenly I felt a warm n' wet sensation on my crotch. When I opened my pants, there was fucking CUM everywhere and my dick was pumping out jizz everywhere. FUCK!!!!
Bob: Just another Penis's Revenge.