Similar to wet willy in which one person licks one of their fingers and inserts it into the vagina in an attempt of foreplay or to create more lubrication.
girl: im all dried out
boy: let me give you a wet philly
8👍 3👎
Taking your index finger, sticking it up your ass, and then putting it in another person's ear.
It is similar to a wet willy, except with shit on your finger instead of saliva, which shares a similar color with the steak on Philly cheesesteaks (hence its name).
John- "I totally just gave Janet a wet philly!"
Billy- "No fucking way dude let's go!!! #ftb"