Love anal play, not very experienced but what I've done so far, I love it and want to explore as much as I can take. Not into pain but am anxious to experience a beautiful woman behind me giving me a vibrating strap-on and slowly switching to bigger and bigger.
You might want to do a little reading on what chastity is truly about with a keyholder. When you hand over the keys it's entirely about her pleasure, not yours. She may be generous and bend you over or she may require you to just orally pleasure her while you strain in your cage. Heck she may ignore you completely and take a lover while you do the laundry and scrub the toilet. In any case, be careful for what you wish.
Any relationship is needs a fair balance. For you that might be seeing how far you can go and discoivering your limits whilst maybe being helped to exceed them by a loving yet strict dominant lady You also have to ask yourself what she needs and desires out the relationship. What makes this beutiful woman want to be with you and push your boundries. When you get that the sky is the limiy.