Neotenize

[Dianne]

To consciously garb oneself with child-like attires to look superyoung; or to give the effect of [neoteny], [pubefantilism], a [babyface] etc.

[Sarah]

To cause to become neotenic; to breed (a domestic animal) to retain juvenile characteristics in adulthood. Also: to endow (a person or animal) with immature features or attributes; to make juvenile in appearance or behaviour.