Dollification is the process of evolving, both mentally and physically, into a doll-like state, like a living doll.
The submissive would take the role of the doll and the dominant would take the role of the doll's owner. The doll would be totally subservient to the owner.
The physical elements of this kind of play would involve the doll being dressed as a type of doll, whether a traditional doll (which would be similar to sissy fetish, or like a Barbie doll, for example.
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Bimbofication is similar in nature.