A slang word in existence since around 2013 used to describe the act of 'ripping someone a new one' or giving them a 'jolly good scolding'. All in all, it's meant in good fun. Mastery of the word can be achieved with regular use, although it's utilization has tended to evolve over time.
Further sub-definitions can be added for different situations. Eg. Family reaming, pre-reaming, literary reaming, full metal reaming, gentle reaming and so forth.
"Oh my God, Jessica. Did you hear what Felipe said about you yesterday? You need to give him a solid reaming!"
"Seriously, I can't believe your work place is pulling that passive aggressive bullshit on you. Go and ream them, hon."
Becky: Did they just ...? I can't believe the stupidity of these people!
Jessica: Right?! A group of adults behaving like children. I can't even ... my brain hurts.
Becky: Just ream them. Ream them all.