CookNFeedin:
Not sure I'd be able to provide better directions in the talk than the link you got earlier. Best I can say, is be open and honest. Certain things you'll need to accept the feedback on. It's your body, but you're not the only one that likes to play with your penis(I assume) so her opinion matters. Introducing her to this site or one similar so she can see the big picture may also not be a terrible idea if she's receptive. If she's already on board with fem dom, there are other aspects of this fetish that can lean into that.
As a domme feeder, I concur.
For example, a large fupa can easily be part of humiliation, feminization, or chasity play. So if she isn't okay with the length loss, you might be able to compromise by tapping into other forms of play similar to your interests.
