Eat a heavy meal, especially one with lots of raw fats (which
are healthy and have a cleansing healing effect; it's cooked and
fried fats which are toxic and cancer causing), eg. raw avocado,
raw coconut, raw eggs, raw sashimi, etc.
Any heavy meal will do, but raw fats does help to soothe the
nervous system, including helping you fall asleep peacefully. When
more blood is diverted away from other parts of body (including the
brain), and into the small intestine area to carry away the
digested food nutrients, you will naturally feel sleepy and tired.
(So don't sit for exam after a heavy meal!).