This got taken down and told me to make the flair this but I’m looking for advice

So my girlfriend and I have been into the sissy stuff for a couple months now ever since I slowly started talking about it and opening up more. I have a chastity cage, and she calls me a sissy and a beta and partakes in sph, feminization, and femdom. However we also kind of talk about how I want to be locked up, tied to a chair, and watch her fuck a bigger manlier cock. She goes along with and says it’s hot, and seems into it. She wants me to wear a strapon while wearing chastity and fuck her with that, so I know she’s into withholding her pussy from me and making me watch. But I don’t know how to mention even in roleplay that I want a bigger stronger alpha male to fuck the shit out of her. I don’t actually want to see that happen because it would definitely break my heart, and I don’t think she is actually open to that, but I want to roleplay and talk to her ab that stuff. Maybe have her jerk me off while looking at biggger studs online and telling me what she would let them do and how they are bigger and better than me

How should I bring it up/ what should I say?