Teens, Tweens & those without any reasonable social skills who "self-identify" with whatever the latest goth and/or vampire "fashion" is "in", and believe that their participation makes them part of something "real", "deep" & "Spiritual". Back in the '80 they were called "Art Fags".
Look at that little VamPoser over there -- just how much glitter is that dude wearing on his skin?
In music, vamping is the repeated use of a phrase through an entire song or the improvisation on top of a repeated phrase through a song. Looping, samples and grooves are all examples of vamping, as is almost all popularmusic with repeated chord progressions. It is not a negative attribute, but implies building on top of a groove to create a song.
The keyboardist used extensive vamping to create an intricate song based on a funkgroove.