What is G6 anyway?

Tweet

Recently, i heard the word "G6" (i am not sure it is a word anyway..) so often i am wondering what is the meaning of G6 actually..Is there anyone who can give a enlightment about this? there is one song always play in my head when i think about this G6.. the beat of the song is very energetic, i think the title of the song is G6, part of the lyric is "like a G6". Anyone know that song? and the meaning of that G6? I am so curious..! I wonder why G6 is such a new trend now.. :) thanks for your help! :)