There are different levels of domination, just as there are different levels of submission. Certainly, I have the discussion and agreement prior to tying her up, spanking her and other, shall we say,
intense, activities.
I know that a woman is "down" with it, by how she responds to me, to my conversation, my body language etc. For example, I was once in a Moroccan restaurant, and there was a belly dancer who came around to all of the tables. She'd motion for some guy to stand up and dance with her, and proceed to playfully tie his wrists with one of her scarves, much to the amusement of the rest of the diners. When she came to my table, and invited me to play, I stood up, and gave her the "stare", watched her catch her breath, and bite her lower lip. When she tried to tie my hands, I snatched the scarf from her and quickly tied one of her wrists, keeping eye contact with her. She immediately turned around and put her other had behind her back. At that point, I clearly had permission to finish it up, so I did, much to the amusement of myself, her, and everyone at my table, including my wife.
Not all agreements need to be verbal.
Now, did I take her home that night, slap a collar on her, proclaim her mine, tie her up, and whip her? Of course not. Did I dominate her? Yes. Did he submit to that? Again, yes. But, clearly, this was not a lasting relationship. Hell, it wasn't a relationship at *all*. But, it was fun for a few moments -- for all of us.