Originated as a term used to describe pulling a wheely on ones bicycle but has since evolved into a commonly heard piece of street banter.
On seeing your friend on the other side of the street, or perhaps whilst passing in a car with the window rolled down as a friendly rousing gesture shout "Uuuuuuuuup bys!" with raising pitch on the 'up' and even higher pitch for the secondary 'bys'.
by anna apple October 12, 2003
buy the domain for your foodie vlog