What is the appropriate technique to stimulate a baby to breathe?

One can stimulate a baby to breathe by slapping  his butt or by flicking the soles of his feet. This is normally done in order to stimulate a baby to take his first breath through the process of crying. Crying will force the baby to take his first breath and at the same time, it will enable the lungs and the airways to be cleared of liquid substances. 

Ihaven't done that yet, so no idea,but this is not the right place to ask