There's two parts of this: First of all, you have to get the data out of the selected Nepleslian male. The best way to do this in the setting is Yamataian mind-reading backup copy machines (e.g. "Soul Transfer"). So you record the training and select the parts you want (Yamatai has computers that are good at this and for this that can help).
The second part is getting the training data into the Youngling. You can do this with the same mind transfer machine or there's also ways to remotely download it via Nekovalkyrja "telepathy." Think "Whoa. I know kung-fu" from The Matrix. IIRC the neko mother also has ways to push info to an unborn youngling as well.
In the RP it's also been seen that Nepleslian men can and sometimes do transfer...