(adjective) The term used for when you're dapping up your bois and grillz. It is the present participle form of "Choo", which is what you say when you dap up your homies/brothers.
Brother 1: "Yo my boi what's good witchu!"
Brother 2: "Ayo what's good witchu brother!"
Brother 1 and Brother 2: *daps each other* "Chooooooooooooooooo!"
Brother 3: "You two really do love Chooing don't you!"
The use of the word "blue" to refer to sexually explicit content was first recorded in Scotland in 1824. "Blue" meant "lewd" because prostitutes dressed in blue gowns.