A charge added on to the price of an item that one must pay a person who is buying said item so that the middleman can profit from the deal. Usually enacted when a minor is paying someone of age to buy alcohol or tobacco for them.
The damn middleman's tax is so high these days, I had to pay my brother 20 bucks for a fifth of smirnoff!
To flip one the bird, usually from a fired worker to their superior as a last "fuck you". More emphasis on one's extreme hate can be expressed by using both hands.
John: My boss fired me today, right in front of everyone.
Mike: Shit, man! What did you do?
John: I gave him the middleman's salute and got the hell out.
When you take a nasty poop and you use the bidet and it still didn't get all of it ....so you have to turn the bidet on and reach underneath and scrub with your left hand
Why is there a big Gulp cup in the bathroom at 7-11? Oh. You have never had a Pakistani Middleman have you?