It is thought that its origin dates back to the wild west in the 1800's, where a cowboy would have to tie up his horse to a hitching post before he could go into the saloon and get drunk.
A British slang for this term, "tie a bun on", also means "to get drunk", however nobody is quite sure how someone came up with that one...
Trying to figure out the meaning behind these slangs is making my head hurt...and driving me to tie one on.
To tie one drinking session to another before the effects/consequences of the last have expired.
Guy 1: Hey, what's going on there?
Guy 2: I'm hungover as fuck, they had quarter pitcher night at Jake's last night.
Guy 1: So you're just going to hang out?
Guy 2: Fuck it lets tie one on.
Guy 1&2: *Crack open beers and commence drinking*