How to do prophylactic breathing?

you first breath in and then you breath out

Prophylactic basically means "preventative." When used as a noun, it most commonly means a condom, but it can be applied as an adjective to any device or method intended to prevent a disease.

Breathing is the exchange of gases between the cells of an organism and the external evironment.In simple words: Ventilation,or bringing oxigen into the lungs and Circulation,or transporting the...

In through your nose, out through your mouth unless otherwise directed.

No. Plants have tiny holes in the bottom of their leaves that take in oxygen. Also, plants don't have lungs.