A strapon. A big one.

[WIP] Every mother should watch her cuck son take in his first dildo/strap-on as his sister fucks him. And then be educated on how to be a beta. "Its fine Kiba. You are just a cuck. Don't worry Kiba. No matter, you are my son. I think its high time I start teaching you properly." After all, it somewhat becomes a mother's duty to teach her son how to serve Alpha if he ever turns out to be a cuck. [WIP]