Looking for Advice on Pegging My Key Holder

I’m hoping some of you more experienced members can help me out and especially key holders too. My KH and I have been practicing MC for the better part of 6 months now. Things are going slow but it’s been great for both of us and I would certainly say it’s improved our relationship. I think maybe why our progression with MC is a little slower is because I couldn’t wear my device for more than 2 or 3 days at a time because I would get mild edema at that point and it would have to come off. Which has been fine because my KH likes to play with me and give me a release at that point anyway. So by no means is what we have “traditional” chastity because of how often I’m let out. I’m hoping that with my adjustments made to my current device, plus I ordered a couple of steel knockoffs with a more open design that me being able to stay in longer will drive my KH’s dominant side. I’ve brought this up in the past to her way before we started MC but I want nothing more than for her to peg me. She already knows she’s in charge in bed. I follow only what she wants and tells me to do so that’s already established. I’ve explained to her that I want to feel what it’s like to be in the traditional female position so I know what it’s like to be penetrated by my partner and fucked good by her. She is reluctant to try this but seems to be opening up more to the idea. I hate to be annoying or pushy about it because I don’t want to top from the bottom. Does anyone have any suggestions, advice or ideas that I could relay to my KH to make her more comfortable with the idea of pegging? I’m not exactly sure what she’s opposed to unless she’s just nervous about trying it because of expectations. I know it doesn’t gross her our because sometimes she like to finger me if she really horny. Anyway any help would be nice. Thanks!