How to be better at receiving pegging?

Often the emphasis of effort in pegging is on the person in the dominant position, however as a sub, how can I be better at receiving for her? I mean this both physically and in terms of the feedback I give her. What do subs do that make a pegging experience exciting for the dom?

Firstly in terms of the way I behave during, I'm still getting used to this, and my dom's demeanour during pegging isn't so much someone lost in the pure pleasure of orgasm but a stoic demonstration of power. I feel like the act of subjugating me through this act is what brings her satisfaction more than the feeling of sex. How can I behave that would make this as pleasurable as possible for her?

Secondly, physically, I want to be able to cope with it more. She's conscious of my limits, but physically we're very different builds. She has very well developed, powerful lower body muscle whereas I'm more of the tall, lean type with thin legs. Naturally her ability to thrust is potentially very powerful and I don't want her to have to hold back so much. Would gaining some mass assist the sub in taking what the dom has to offer?

Thanks and sorry if these questions seem silly