Doing a "Colin" 

To intentionally slur or defame someone under the pretext of being a friend.

To shit-stir because you can.

Why is Fred so pissed off?
Oh, Sandra is Doing a "Colin" and telling him everyone hates his new haircut.

Doing a "Colin" by The Master of Disaster! January 19, 2015

Doing a Colin

To "do a Colin" is a synonym for any broken promise/lie.

Spawned from the twitter trend #IamColin. In reference to twitter user @cwarr07 who promised to donate 100 pounds to a cancer charity if he lost a bet. He lost and refused to pay. This started a twitter trend where people have been donating on his behalf to the Sir Bobby Robson Foundation raising almost 1000 pounds.

John: "Fred promised to help me with moving house last week. On the day he never showed up or answered his phone."

Terry: "Fuck him, he's always Doing a Colin"

Doing a Colin by toonarmymia July 29, 2011

Doing a cling 

Someone who only has friends that smokes weed (ain’t that suspicious)

Look at him he’s doing a cling

Doing a cling by Yo-yo a dooo February 26, 2021