I love a thin-crust New York style pizza so loaded with cheese and pepperoni as to preclude the hot slice supporting its own weight.
I slip a slice onto tripled-up thick paper plates at the pizza place (as anyone who loves NY pizza knows, if it ain't greasy, it ain't good), then slip enough off the edge to allow me to take a bite. When the pizza's cooled enough to be able to have my hand support it without me burning my fingers, I'll prop up the crust with the fingertips of my left hand while shoving it into my mouth with my right.
Napkins are used in quantity, though if it's gonna be laundry day the next day anyway I just wipe on my pants---a good detergent gets the grease out and I get to smell like pizza for the rest of the day.