The female Dom is definitely Marianne. Apart from recognising her voice and tits, I also recognise her technique with women. And at 16:45 you see her face. By this time she'd come a long way from her early stuff with Yvette.
Lovely piece of diversion. Both women wear wedding rings and the sub has had a caesarean. It is obviously a film made for the pleasure of those taking part and it would be lovely to see more of both women.