A classic bit is the act of doing something "classic". A bit is anything you can be doing or about to do. So when one performs a classic bit they are doing something that is classic. Or in other words really cool.
Person 1: Hey can we do the McDonalds bit?
Person 2: Yeah dude that's classic
Two people are stuck in traffic
Person 1: This sucks
Person 2: yeah we are deff doin a Classic bit right now
Person 1: what bit is that
Person 2: oh you know the Classic stuck in traffic bit
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