Top definition
An occurence during intercourse between male and female where (usually in the doggy position), the mans purple headed yoghurt slinger slips out of the vagina and into the asshole but instead of stopping they come to a mutual decision to continue anyway.
steve: oh fuck my dick just slipped into your shitebox!

betty: wow! that feels really good lets keep going!

steve: fuck yea! i just accomplished the bifkin train!
by conzadizzle January 19, 2011
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