I have read a lot about rendering sex more interesting by trying to avoid falling into an always-the-same-procedure routine. Likewise, I have read a lot about having conversations with one's partner about each other's wishes, desires, and what one would feel comfortable with (i.e. what one would consent to). Both seem reasonable and desirable to me.
Now, I am a bit clueless about how to apply this in practice with my partner (I am male, she is female in case it plays any role). I do not consider myself very sexually experienced. However, one thing I have (unfortunately?) learned in the course of our relationship is that talking or asking about whether she feels comfortable trying this or that does not do any good (neither during physically intimate moments, nor at any other time). The answer is always "No, I don't want that.", "No, that's not possible.", "No, it's not necessary, don't do it.", "No, it won't be pleasurable for me.", etc. All right, so put these actions mentally on my no-go list and look for other things to try.
In the heat of the moment, I also sometimes did a few things that I had never asked her about beforehand. I feel somewhat sorry for that because I know it's not the "proper procedure". Yet, without any exception, she not only seemed to enjoy them, but occasionally asks me to repeat them for her. (Note that I'm not talking about "advanced" actions like oral sex or inserting fingers or anything - no-go list, see above -, more on the level of massaging her breasts and similar.)
Now, I would like to find some "advanced" actions that she does like, but I have become downright wary of both asking (because I am pretty certain it will be shut down) and just doing without asking (for obvious reasons, don't want to do stuff without knowing she feels comfortable about it). She blocks any attempt to talk about it, having repeatedly expressed a stance along the lines of: "Let's just do it, why do we have to talk about it? That's a huge turn-off for me."
How can I handle this communication issue?