I think I found a cheap and easy way for stress reduction that requires no training. The idea is probably not new since it’s very simple. Just fill a soda bottle (1.5L) with hot water and cover it with something like a fleece fabric. Then use it together with a pillow touching your face. For me focusing on the heat outside but close to the body helped me reduce the stress. A rubber bottle would probably work even better. The soda bottle is still quite effective in my opinion. Even if you don’t feel stress it should give you comfort during the cold winter months. Note: Do not use very hot or boiling water.