This excerpt is from a write up that details an interview with Adam Phillips on this topic. Both links are included below:
PHILLIPS: That idea was one of Winnicott’s most radical, because what he was saying was that solitude was prior to the wish to transgress. That there’s something deeply important about the early experience of being in the presence of somebody without being impinged upon by their demands, and without them needing you to make a demand on them. And that this creates a space internally into which one can be absorbed. In order to be absorbed one has to feel sufficiently safe, as though there is some shield, or somebody guarding you against dangers such that you can “forget yourself ” and absorb yourself, in a book, say. Or, for the child, in a game. It must be one of the precursors of reading, I suppose. I think for Winnicott it would be the definition of a good relationship if, in the relationship, you would be free to be absorbed in something else.