I did this and had positive results. I didn't do the "hand in skin" part, because he had his clothes on and when I tried putting my hand inside his clothes it

I did this and had positive results. I didn't do the "hand in skin" part, because he had his clothes on and when I tried putting my hand inside his clothes it just annoyed him more. He was having a tantrum. I sat on the couch and sat him on my lap facing me. I pulled him towards me chest on chest. He quickly got more annoyed to be held down but I kept him there. I started doing deep breaths. It took him a bit to realize that we were "doing something" but slowly he started settling down and within 10 minutes he had stopped crying. This is in contrast with "normal" where if I hold him down while having a tantrum it just escalates. Eventually I stopped when I noticed that he was about to fall asleep. It's unclear whether the deep breaths actually contributed or whether this was just a lucky one-off. I'll continue this.