It is also spelt "All the Boiz" It is usually a close group of friends, mainly four guys. Who are good friends and hang out together! When they hang out they usually talk about, sex, drugs, girls, parties.
An ATB style group usually shares resemblance to the British tv show "The Inbetweeners" (A group of four teenage boys in high school)
Guy 2:Oh, not much just hanging out with ATB!
Guy 1:Sounds good man, what are you gonna do
Guy 2:Not much, just chill and kick it Inbetweeners style
Woman. "No problem, you can get me going by giving me an A.T.B."
Man. "Fuck you, we had an indian take away last night, your ring will be nasty"
Woman. "Fine, have a wank instead!"