I went to an indie once in Newcastle and fancied the maid more than the wg and quite brazenly asked the maid if she was up for a session, right there in front of the wg. The maid laughed, told me she was pregnant and not a working girl.
Not to be put-off, I made her an offer I thought she couldn't refuse to sit on my face. She politely declined again, making it clear she didn't want to step on the wg's toes. The wg was very patient while all of this was going on, btw.
However, i really fancied the maid so I suggested we have a 3sum, with the maid sat on my kipper. They both agreed and much to the wg's credit, she showed no visible signs of jealously and just took it all in her stride.
Now that's professionalism for you.