Baby play is an adult sexual deviant whom gets pleasure out of being treated like a baby, both phsyically and mentally. Such as: (soiling diapers and being changed, being breast fed, goo-goo ga ga talk, wearing bonnets, pacifiers, holding a rattle etc.)
Dude, I walked in on Kirby and this hooker! She had him sprawled out on the bed changing a shitty diaper he was wearing! Kirby is into baby play BIG TIME!