1: Intricate, fast, and unbelievably skillful playing of guitar, Usually referring to a solo or just random shredding.
2: A substitute for "Unbelievable", "Amazing", "Astounding", and other remarks of extreme approval; Usually referring to music.
3: World Of Warcraft
-specific slang for the Shadow Priest class.
4: A term for when a man ejaculates a large quantity of semen on a woman's face, thus giving it the appearance of "melting"
1) The guitar on Through The Fire And Flames by Dragonforce
is facemelting with it's speed and melody.
2) The band Joe had playing on the stereo was facemeltingly good.
3) I was grinding my paladin up some levels when this jerk obliterated me with his facemelter.
4) The facemelter, as seen in countless pornographic videos and pictures.