Skinny Mike was 15 when their series started. And yeah, that first session is pretty infamous for the reason you described.
Mike's addition to the Big Connor series was the solution Charlie Nathan introduced to keep the element of underage performers intact after Connor himself had turned 18. And he pretty much hit the jackpot when Mike immediately responded to Connor's stimulations. It sounds crude, but the TeenAthletes / Fitvidstore / Flexvidstore business model has always required this element. Remember, most of their most famous models (Big Connor, Jake Schellenschlager, GeordieFlex, KieranFlex, The Basilisk, Decoste Ables Jr.) were all underage themselves when they started doing videos, either public or private customs. It's only in the last two or so years that Flexvidstore has ónly contained adult models (it was always a mix before), although they do still sometimes sell Andrey Moroz videos through his brother's channel, and I'm not sure Andrey's of age yet.
It's honestly stunning that in this day and age he's kept his company up and running.