Okay, for a start the offer would always be appreciated, in the same way that someone of either gender telling me they find me attractive or want sex with me would be usually be welcome, I'd take it as a compliment and feel genuinely honoured to be thought of, even if I wasn't interested in the person/people.

If I was comfy with the girls and I thought Sharon would be fine with it (or I rang her on the mobile and checked she was and/or my limitations (Kali would only cheer me on and say 'Go for it!', she thinks I deserve to be out there playing around)) I'd join in, watch, take pictures... whatever felt comfortable to me and whoever was involved.

The most important aspect is feeling comfortable and right at the start, then I can follow wherever it leads quite naturally.