guyser Share definition Flag A sexual position in which a man titty fucks another man that has large enough man-boobs to allow such a vile act. That guy is so overweight that his tits are so huge that you can give him a guyser. guyser by Pacos Bill April 30, 2008 0 0 Get merch Get the guyser mug. Buy Now — $32.95 See more merch