msfk Share definition Flag is a band of guys that gangbang people and get bitches. Pussybois will say that they are apart but they are not and get flamed "bruh last night was lit cause me and my bois got to go msfk on two thick girls''. msfk by lkoool November 24, 2017 0 0 Get merch Get the msfk mug. Buy Now — $32.95 See more merch