a form of role-play often an element of bdsm play, age play is most often used to refer to both 'adult babies' and adolescent role exploration.

Adult-babies involve people who take an infant role, with another adult taking a caretaker or parent role. Reportedly this form of roleplay can be quite amusing in an S&M-oriented dungeon.

More frequently ageplay is roleplay usually involving adolescent roles / fantasies, such as catholic school girls or Daddy-boy relationships. Often this is a means of visiting or accessing issues from that time.

Neither of these activities is related to pedophilia. Ageplay (or something like it) is a common element of 'accepted' societal humor and roleplay, In addition to being a common element of alternate sexuality / relationship or leathersex.