There are several actions, as long as you persist, you will have good results. The first one is to lift dumbbells. You can buy two very light dumbbells at home, or you can directly lift them vertically with two water bottles. Not too fast, ten and fifty dumbbells a day.
The second is side lift, which is also suitable for dumbbells or water bottles. Lift it up slowly, put it down and feel the process of exerting yourself. It is also a group of ten, five groups a day, and long-term persistence will have good results.
The third is that I often go to work without any exercise tools. I have a belt as wide as my shoulder. I may go from my chest to my back, but there is no problem. As long as I slowly change the distance, my back and upper arms can be improved.
I suggest you find a video, which is used to warm up the ballet dance. He knows several gestures, all of which can open his body well. As long as every action is up to standard, it will have an effect. I'm afraid I can't hold on. Three days of fishing and two days of drying nets, no one can shake off your swan sleeves.
Some professional movements, such as rowing with dumbbells, are not easy to do at home. I think simple actions are enough. You can do it anywhere. I suggest you download a keep. Every place in it has professional training. I followed it for a while before, and it felt good. But he has some professional movements, so you must pay attention to his strength, don't practice blindly, be simple. I recommend Duoyan Zheng's weight-loss exercise, which also has a good improvement effect on butterfly sleeve.