That’s not the reason, it’s because the constant removal & reinsertion of the cartridge across attempts to get it working causes the pins on the inside of the console to scrape against the contacts on the cartridge enough to remove some corrosion and form a proper connection. Saliva and the blowing had little or nothing to do with it.

The proper method is to use contact cleaner, rubbing alcohol or an eraser to remove the corrosion from the contacts on the cartridge. This is basically the same thing but instead of scraping off the corrosion with the console cartridge slot pins, you’re removing it evenly and cleanly.