Masturbomber

Someone or something that awkwardly(inappropriately) and unexpectedly interrupts somebody’s intimate self-pleasuring session.

A play on the term photobomb/photobomber.

“Dude, I was fapping so hard yesterday and was really getting into it until my dog jumped on my bed and started licking my face! He’s the biggest Masturbomber!

His new nickname is Masturbombus!
Verb- Masturbomb
Noun- Masturbomber