Wow, all pink. That's like a yoga move. Sometimes we'd start the class sitting in lotus position with our thumb on one nostril and ring finger and pinky on the other. We'd completely exhale out all the air from one nostril to the count of eight inhale to the count of four. Hold. Exhale the other side for eight. Inhale for four. Hold. Exhale the other ... Sometimes I'd fake it during runny nose season.
It's supposed to balance the hemispheres of your brain and draw attention to the breath. Of course, this kind of yoga isn't really for 5 yr olds. While some small kids go with mommy to yoga and do quite well, usually children do a different yoga.