1991, Robert T. Francoeur [ed.], Timothy Perper, and Norman A. Scherzer, A Descriptive Dictionary and Atlas of Sexology, page 186〃 (Greenwood Press; ISBN 0313259437, 9780313259432):
[…] activity may be replayed during masturbation (qv) or copulation (qv) with an older partner. The reciprocal condition is paraphilic adolescentilism (qv), in which an older person impersonates an adolescent in order to achieve sexual arousal and orgasm.
Teenism: A psychiatrist acquaintance tells me the preferred medical term for this kink is adolescentilism but when I told a teeniest of this, he replied, “Yeah? Well, your shrink friend sucks. Or maybe he blows. Dumbass.” Many conversations I had with teenists were similar in nature.