Had a situation somewhat like this, but not exactly. A nice looking woman, who worked in the same building with me, (I knew her just to say hi in passing), came into my office one day. She closed the door behind her and told me she wanted to ".....sit on my face". I was so stunned, my mouth fell open, I'm sure I turned red, and all I could do to reply was stutter, "uh,uh,uh....". She stood there for about a minute, smiling. When I didn't reply with anything intelligent, she turned and left. Being somewhat shy, I wasn't able to approach her and she never offered again. Damn!!!!!
By the by, I consider myself good looking. Check out my avatar. That's not me, but we look similar.
Two women together just seem natural. The female body is beautiful and artful. 
