Not that anyone is interested in this, but I thought I'd post the end of the story, just for continuity's sake.
Yes, Lily and I did get spanked. In front of each other. With scolding and sternness and red bottoms and everything.
M required that we both wear skirts and we both complied, like the good girls we are. I wore my new Victoria's Secret panties that say "Angel" on them, just for good luck and subliminal messaging. Lily wore a thong, practical girl.
And she got to go first, lucky duck. I think M was trying to be nice because she's never had a spanking for punishment before. He had us both sit down on the (hard wood) coffee table and he stood over us, gently scolding and reminding us why we were there and what was going to happen. Then he sat down on the couch and held out his hand to Lily. She glanced at me a little nervously and I gave her a supportive smile as she gingerly put her hand in M's. He pulled her up and over his knee and raised her skirt. He caressed her backside briefly and then started spanking. On the whole it was definitely not the hardest spanking I've ever seen, but her bottom turned an alluring shade of red (sorry, Lily!) and she squirmed delightfully. Of course, I could only partly enjoy it because I knew that my turn was next and included the ebony hairbrush. Lily did feel the wrath of Ian's Nanny Paddle, but was spared any ebony because of her inexperience.
Oh, and [mumble, mumble] it happened [mumble] to be a [mumblerepeatmumble] offense for me.
And then it was my turn. Even though Lily was nursing a beautiful pink bottom, I believe she was rapt in attention. I got the barest of warmups, a short stern scolding, and then the damn hairbrush. Which came down far too hard, far too many times. Not the hardest or longest spanking of my life, but certainly a memorable one, if only for the presence of a comrade/witness.
Not that anyone's interested in this part either, but there were lots of cuddles and kisses afterward. We both said our obligatory thank yous and were forgiven.
Now I just need to buy some spray-on sunscreen. Or maybe steal Lily's. ;-)