Tie : nf A tie is a strip of cloth, usually narrow and long, that men tie around their necks.
Familiar phrase: Throw one in ( ) behind the tie (to drink, especiallyalcohol).
The tie, which starts from the neck and goes down vertically, "hides" inside the body a very useful conduit for ordinary people, a pipe whose role is to bring the liquids swallowed up to the stomach. .
And it is the fact that the tie is fixed to the neck which made that, in the slang of the XXth century, the term also designates the throat, this place which is the obligatory point of passage of all that one swallows if we are not taking a wrong turn.
From the neck (p), even if we imagine that the expression should rather use in instead of behind, its meaning becomes as clear as a glass of vodka, the rear which can also have a connotation of discretion, of sneaking consumption, but with connivance between drinkers.
See Candy tie.