1.to laze around at a particular meeting place for interactions between yourself and your peers
2.sitting down doing nuthing in particular, just being bored
Joe: hey Andy im bored, wanna go bum it?
Andy: fuk outh!
Chris: what have u been up to?
Bill: nuthing, just bumming it
John: Hey Mark how was ur daii todaii?
Mark: fukn gay, just bumed it