the horizontal monster mash Share definition Flag sex with a chick... fucking a chick, banging a chick.. that sort of thing omfg! Their doing the Horizontal Monster Mash on my leg!!! (WTF?) the horizontal monster mash by teh_n00berx0r June 12, 2006 0 0 Get merch Get the the horizontal monster mash mug. Buy Now — $32.95 See more merch