I think falling a sleep at will can be done by either getting too tired or too bored. I generally watch / read something really boring (e.g. I cannot stand biol

I think falling a sleep at will can be done by either getting too tired or too bored. I generally watch / read something really boring (e.g. I cannot stand biology related books or youtube video teaching biology. Sometimes I force my self to watch / read a boring books / videos and in 15min I start yawning and soon sleep. Another thing I do is I climb stairs to my house (I stay on the 6th floor and have to climb more than 100 steps)