A term to put others in their place much like pwn, or pwnage but better, widely used in the gaming world. Literaly it means: Sandwich Making Nipple Flicking Action but its meaning delves much further than that.
"That was pure Smnfa'ge bob"
"I just Smnfa'ed Bob in the A.. to the max!"
"One time i caught bob doin his sister, and I though.. damn shes smnfa'in hot"