When you open the door with out any screens to let the cool air in the house because you do not have air-conditioning.
The trailer's front door was wide open letting in all of the flys from the chicken farm where he was a migrant worker,to let in the fresh air because mexican air-conditioning was better than none at all.
The act of driving a vehicle that has no (working) A/C with all the windows open or driving a convertible with the top down. Also can be used to describe a school bus that doesn't have a/c.
This bus doesn't have A/C so lets use the Mexican Air Conditioning