I felt sleepy. I was in Hokkaido Japan in winter, sitting in a pool at an onsen. The water was very hot and it made you feel sleepy.
When you are in the onsen, you have to be naked. You have to rinse yourself before you get into the pool. There are lots of pools. There is one pool which is good for your skin, another one is a fountain pool and one pool that is ginormous. You are not allowed to run, splash or dive. You can't stay in the pools too long or else you will faint.
When you are done, you go to a section where you sit on a stool to bath. You just sit on a stool then you just soap yourself. When you are done, rinse the stool. I would want an onsen in my bathroom at home.