I'm new to soldering so please bear with me

I've recently read a couple of people suggest that when quick soldering a modchip you can just melt the solder and let it "fall" into place without ever letting the iron touch any of the surfaces.

Wouldn't this result in a "cold", poor quality solder joint? From what I've read all of the surfaces in contact with the solder need to be heated for a good solder joint/optimal conductivity.

Please feel free to correct me if I'm off base!