look up any word, like bukkake:
 
2.
To kick someone in the chin before they even know you're about to kick them at all.
He started chattin smack so I flashkicked the mofo.
by Joodas August 10, 2004
 
1.
a backflip/back tuck with a kick at the height of the flip.
a prerequist to the flash gainer which is more advanced and done usually off one foot while moving foreward
I went out on the soccer fields and pulled off a few flash kicks.
by Anerky December 31, 2005