Thanks to some of the responses in this thread (where some ladies claimed to enjoy this kind of thing), I went out a little bit on a limb and tried something similar with my W, as she has expressed things to me in the past that would indicate she would be into this sort of thing. Turns out she f-ing loves it!

I think it needs to be the right situation though, I wouldn't do this every time, and I think the sex has to be particularly dirty and even rough for this kind of "ending" to be fitting. It would be awkward to be having loving, vanilla sex and then suddenly pull out and finish on her face/in her mouth, but to each their own! I always knew she's pretty submissive and likes to be controlled, even degraded/talked down to (in bed), but she confirmed with me she would rather not be asked or warned, just as some people in this thread said. She wants me to just do what I want to her, even if she resists a little. She thinks its hot. A little confusing but I think I can read her well enough to know when she really doesn't want something.