When you stick your tongue out at someone, your tongue usually makes contact with your lips. If you pay close enough attention, and add a little air to it all, it sounds like spf, short for Spiff.
When Julie stuck her tongue out at Eric, she breathed out a bit causing a spf noise.
by Heymbit January 28, 2008
The French term for homeless/bum/vagrant. "Sans Premesis Fixe", Without a fixed residence. I think that phrase better sums up these people than "bum."
"I used to see SPFs peeing in public all the time when I lived in New York."
by Mitchell B. July 14, 2006