This is a qigong practice where you cool the body down into sleep, i couldn't find one image but basically you perform the healing sound "heeee" over and over until you fall asleep haha, it works really well.  I put together some images to give you the idea.

https://imgur.com/QkmZC8g
https://imgur.com/xh0NSaA
https://imgur.com/8kOG1Rs

The whole practice illustrating how it"would look" :)  https://imgur.com/5cXTJQt