I recently had the opportunity to experience Reiki and despite multiple attempts by different people to explain reiki I never really fully understood it. Eventually, I friend bought me a session for my birthday, and I too find myself in the category of not fully being able to describe it.
I tell all my friends and family how amazing it is, then struggle to convey the experience. All I can say to anyone vaguely interested in trying it, is to have a go, experience it for yourself.