What do you need: Safe and quiet space with a place to lay down or a chair to sit on in a comfortable position.
What can it help for: Promotes concentration, mindfulness, relaxation.
How much time do you need: Up to 2 minutes. 
How to do it?
Expand the palm of your left hand in front of you, and with the index finger of your right hand, draw up and down between the fingers starting from your thumb, continuing until your little finger. 
Inhale through the nose while moving up, and exhale while moving down the finger. 
Continue until you have travelled around all the fingers.
Change direction and move from the little finger back to the thumb.
Find your own breathing pace.
Repeat two more times.