The term means to be fucked from more
than one direction.
Said in almost any situation =D
and is derived from the term
(Fuck me side way's).
Me(doing DIY): 'Shit this radiator is fucked multi directionally!
2xguy: Ahh!!!! Multi-directionally babe!!!!
Girl: WTF!!!! are you playing at!
Fuck-Me-SideWays