It's not rating a minimum power or a recommended power. Most 100-watt car speakers will work perfectly well on factory radio outputs, and you aren't going to do them any harm by trying them out. (Ignore anyone who tells you that you can blow any speaker by using it with too low power an amplifier; this is not true).
Ujjayi breath. Ujjayi breathing is a breathing technique employed in a variety of Taoist and Yoga practices. In relation to Yoga, it is sometimes called the ocean breath. Unlike some other forms of pranayama, the ujjayi breath is typically done in association with asana practice.
Aleix Segura Vendrell, who set a world record for holding his breath underwater for 24 minutes and 3 seconds, is a proponent of this very technique. Don't hold air in your cheeks. This method is meant for an air reserve, which requires letting go of the air in your lungs and switching it with the air in your cheeks.