Memory

Often as I lay down with my youngest trying to get him to fall asleep I think about my breathing. He usually thrashes about, tries to gouge my eyes out, pulls on my beard and kicks me in the groin, and doing that he breaths quite fast. To infuse calm into him I breath calmly and controlled as I, more or less successfully, try to get control of his flailing limbs.
And this always brings me back to when I was young and for some reason or other got to sleep next to my father. I was mesmerized by his slow breathing and I tried to mimic it. A futile task of course since the breathing period depends on how large you are (a humming bird breaths much more rapidly than a blue whale for example), but still a great way to fall asleep since you get oxygen deprivation if you force yourself to breath slower than your medulla oblongata wants you to.