the founder of the term kick her biff was one Jonny Morrell, the term was first mentioned to myself in late 2006. And due to my extensive travels the term in now commonly used in such places as Kaula Lumpur, Singapore, Australia, New Zealand, Fiji, USA and the west midlands!
the word biff has also been adapted into other such insults and suggestions such as biff basher, biff licker, biff puncher, biff juice, biff wiff, biff muncher or just the standard biff kciker(s).
this term/word is also awesome because most girls do not know what it means so you can slip it into conversations and amuse yourself and your buddies! If questiioned as to the meaning of the word biff by and non-biff kicker e.g a gay or prude state it is mearly a name of a chracter from back to the future.
Mate you should totally kick her biff in!