Taking extra sips from the self serve soda fountains before filling your cup and closing the lid. Offenders are usually found hanging out by the soda fountains and continously drinking from the fountain until they feel they have had a satisfactory amount. Usually sampling two or three different flavors and then proceeding to exit the fast food establishment.
"Sip Stealing is required man, how can I tell if the soda gonna be flat or not?"
by Jay Boogie February 22, 2006