Would you do it, if your partner asked for it?

Hubby and I had a discussion about what partners in love would do for each other, sexually. If you are not into anything more than missionary style, anything else already poses a major challenge. For us, it is slightly different: due to our kind of relationship, I always let Master lead and decide (bitchy moments excluded). This has never been a problem, because we have complete trust in each other and even though he decides, I know that he also considers my point of view. This is even more important when you talk about limits. What is ok during a session, what is not? We definitely stick to safe, sane and consensual as the first commandment. We have always talked about what we like and dislike and Master questions me a lot about that, because he wants to make sure that my limits are never crossed. Pushing limits might be ok, if it is done nicely, with a lot of sensitivity.
Master and I have no written list of hard or soft limits, though we have started with such years ago. It has changed over time and especially hard limits are still more or less the same. We talk about such things, but don't write them down any longer and that works for us, because we have been in a relationship for more than a decade. If the above title referred only to an unknown playpartner, the answer would be completely different.
So, what if it was only a minor nuisance that was asked for? No doubts, I would do it for my Master. These things could be only annoying, or just be uncomfortable at times, but nothing that shakes you to the core, therefore, I could handle that, at least for a while.
But what, if Master suddenly wanted something we both dislike completely (hard limit), for example to draw blood? (Mind, it is just an example, and I feel safer with Master than with a complete platoon of Royal Marines, although they are nice guys, too) I would give it a try. If he wanted that, I would try hard and probably fail, because breaching such hard limits would shake my innermost self. This is already one of the worst case scenarios, where you really could expect resistance. If I could not cope with what he wanted, I would ask him to stop.
There is no doubt in me that he would  never be as insensitive, and I know that I enjoy many privileges with him, too. But since there is trust and love between us, it is easy to give what he wants, or at least give it a try. And once again, another key that helps to answer the question is, that we talk and talk and talk. If Master saw that I had problems with something that he wanted me to do, he would not leave me in such a situation unattended, depending on what is going on, he would even stop a session or at least take me out of the situation I have trouble with and we would talk things over. I never get this feeling that I am kept in a state of emotional helplessness. Defenseless, yes, sure, all the time, but that is done willingly and  not a cul-de-sac, Master does that towards me, too. As a result, I can only say, yes, I would do it with Master and for him.