Suggested by Shaker startledoctopus: "What is your favorite self-soothing/self-nurturing activity?"
Honestly? Trichotillomania. I try not to do it, because I give myself bald patches, but it's an unconscious habit, and it is definitely my go-to self-soothing behavior.
When I consciously want to nurture myself, meditation. Outdoors with the dogs, if possible.