To do one's own thing.
To 'give the birdie' to the world and make a concerted effort to annoy / piss off / offend as many people as possible in a given timeframe.
James: Nope - he usually chases pigeons on his lunchbreak.
James: Woah - does Miranda usually dance on tables whilst inebriated, sans underwear??
John: Nope - she's off on one.