I'm not sure if it matters but for context I am 21, Asian, 5'6" and thicc.

I've known for quite a while that I usually take the dominant role in the relationship. I practice taekwondo for more that 10 years and other forms of martial arts. I love the feeling of winning - of being stronger than my opponent. I've only ever been in a "vanilla" relationship. I think I usually suppress my urge to take leads in the relationship because it often scares guys away. 

I get excited by teasing guys, by controlling the power dynamic between us. I get off on their look of anticipation, waiting for me to give them pleasure. 

So, cut to meeting this guy on an app. One thing leads to another and he says that he's into breathplay. He wants to try smothering, and as eager as I am to try it with him, I am nervous as to how to approach it. He wants to go unconscious but I'm not comfortable yet, especially because I have no experience yet. I like the idea more of him being on the verge of unconsciousness but not totally unconscious. We both agree that there will be no ropes around the neck or choking. 

So I guess my questions are:
1. Do you have any advice on breathplay for the first time? Or any stories based on your personal experience as a mistress or as a sub?

2. Based on personal experience, does your D/s relationship extend out of physical intimate moments? Like when dating and the way you interact with your partner in general?