Jacksterback - A memory that pops into your head like a surprise while you'

A memory that pops into your head like a surprise while you're getting off. It might be something you did yesterday or something from way back.

I was jacking off and suddenly I was back in 7th grade getting called out by my teacher.

I had a flash of my first time getting caught jacking off by my mom.

I was getting off and I remembered when I got caught by my brother.