How could the nostril and mouth movements of a frog be described when it is using its lungs to breathe?

To breath in the air, frog lowers the floor of the mouth. That causes throat to expand and nostrils to open. The air enters the mouth through nostrils and after that nostrils close. The floor of the mouth contracts to push the air into the lungs. To breath out the air, the floor of the mouth is lowered again and the air is pushed into the mouth. Nostrils open again and the air leaves the mouth.