Somatic Experiencing is, in some ways, just like it sounds: a direct experiencing of the body and its sensations. Where the magic of this work comes in is experiencing layers of sensation and reaction that have been long covered up — perhaps early life trauma. What can follow from "digesting" this childhood trauma can be monumental in one's now-adult life.
(And there is even research — brought to life in like this Scientific American article, and this one in Nature revealing how trauma that happened well before you were born could be impacting your life now.)
Irene Lyon is a practitioner of SE, and a thinker and healer regarding helping people unwind old trauma patterns. She was a well of insight for me in this talk. I hope you enjoy; you can check Irene's work out via her link below.
Irene's website, including resources, teaching dates and online programs
Wikipedia article on Polyvagal Theory (the dorsal/ventral vagul, which is of course just two branches but are contained within this theory of how works this branch of the Autonomic Nervous System)