Repeating the same mistakes and expecting different results. This is usually done with an obliviousness unfathomable to those in the individual's presence. Can also be used in the context of "getting cherrymanned" in which an individual is submitted to the reoccurring idiocy of another's mistakes, or worse falls into one of their cherry traps.
That noob keeps cherrymanning up the forums with his incessant dribble. Someone should really give him the ban hammer and put him out of his misery.
It's the act of getting as close to "popping" your cherry or having sex and then leaving last second. Considered at pro level if they're still a virgin.
"She didn't leave cause I smelled like shit, she was Cherrymaxxing"
"Was about to get my tip sticky, but she's Cherrymaxxing
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"