The "bin" comes from rubish bin, as in a garbage can. So a "head bin" is someone who isn't known for sound thinking. This is an insult from Northern Ireland.
by Anthony W. Yochmann August 17, 2009
The condition of being so intoxicated you crawl into the fetal position and fall asleep with your head in a bin.
Ceri: Holly was so drunk last night her head was in the bin!
Tommy: Wow, again? Holly's always getting her head in the bin.
Holly: Zzzzz
Tommy: Wow, again? Holly's always getting her head in the bin.
Holly: Zzzzz
by Binhead1000 June 27, 2012