The act of holding your sandwich out in front of you and leaning forward to take a bite so as not to have sandwich drippings ruin your clothes. This act is neccessary when partaking of a sandwich in Philadelpia. It is impossible to eat a Philly cheese steak, WaWa hoagie ect. and not have drippings. Thus the "philly lean" was invented and has saved countless natives and tourist from meat dripping stained clothing.
Yo B you better get your philly lean on or that sandwich gonna ruin your... damn haha! to late nigga! Michelle gonna think your whack as shit if you don't change clothes before your date.