Years ago, I had a the DVD with the producer's and the actors commentary. The commentaries were separated into 3. The producer's was by itself. Two actors, Mark Stevens and Eileen Daly were together. Gry Bay was by herself. From the commentaries, it seemed Gry whined a lot during the whole process. She had developed a real relationship with Mark. She became angry and distraught and stayed that way till the end of the shoot after the blowjob scene between Stevens and Daly. Apparently, Bay was in the next room as it was being filmed and cried and made sounds as loudly as she could throughout the whole time. That scene was already in the script.
She was also difficult during the filming. She agrees to stuff before the filming and then changes her mind during the shoot. One of it was she likes to use her hands or her partner's hands to cover her bits. Things like that. This was verified by the producer and the other actors and in some cases, by Bay herself. The comments did not sound like attacks, just conversational with a little bit of disappointment thrown in.
The producer was also not happy with the director as she made something that was visually different from what they agreed. The movie they agreed to make was supposed to be much more visually explicit than the one made. During her commentary, Bay did not complain about that actor cumming in her. She was very matter of fact about it. She complained about other stuff though, some of it quite petty. So that whole thing about that actor cumming in her and getting her mad has become an urban legend, I'm guessing.
If anyone can find the DVD, it really is an interesting listen. Sadly, I've lost mine long time back when moving house.