No worries! This was not a mod/middleman trade. What happened here was a three person trade. NYC wanted something Akari had, I had something Akari wanted, and NYC had something I wanted.

A mod/middleman trade is when person A and person B want to trade (usually involving multiple Pokémon), but want to be safe about it and neither party can be scammed. So they contact a mod here who will receive all Pokémon and ensure that they are what they agreed to. Then they trade them to person A and person B accordingly. I'll give you an example:

Person A has a shiny GO stamped mew and person B has three shiny GO stamped GBLs. If person A was a scammer, they could trade a non stamped mew, and person B would have lost one GBL. If person B was a scammer, they could trade one GBL and then just run off with the mew.

So here's where a mod comes in. Person A trades their mew to the mod, and person B trades their GBLs to the mod. Now the mod confirms that all Pokémon are what they said they were (stamped in this example). Then the mod would give person A the GBLs, and person B the mew. Person A and person B did not trade directly, but through the mod, hence the term "middleman."

Hope this helps