My wife and I had met the man who would soon become her long term lover for drinks, but not played with him yet. In the hour ride up meet him we discussed that in their chats he revealed being open to things like me sucking him. I was not agreeable, but she seemed intensely excited about it. I agreed that if things worked out long term I would be open minded to considering it, but that it was off limits for now. She agreed, with the caveat that she would have final say on whether she eventually escalated to it, as with all other matters.
She was making out with him and had taken his cock out of his jeans, standing next to a bar in his living room, when she broke their kiss and looked at me, telling me to get on my knees. I didn't say anything, but stood frozen and glared at her. She's very naturally submissive and only really played at being dominant with me to that point. I could see she was not just playing when she glared back and said "I'm not asking cucky, in your knees." A couple minutes later my lips wrapped nervously around a cock for the first time. I was furious with her and yet still felt my clitty throbbing in her cage by the fact she was taking control.
The next hour was filled with him fucking her in various positions, pausing every few minutes to make me taste her on his huge cock. It ended with him fucking her leaning against that same bar. I was on my knees below them and tasted another man's cum for the first time when he slid out of her very well used cunt and I hungrily ate his cum from her dripping pussy. He was still not entirely soft and pushed back inside her as I licked her and he pulled back out pushing his spent cock between my lips for cleaning as well.
I was genuinely upset at her breaching the agreement that we could consider it at some point! She simply reminded me that I had agreed she had final say on when the time was right. It was the beginning of the journey of her pushing me into a sissy role... something I similarly never wanted, but came to crave.