Lynne is out jogging with an unnamed friend. She asks her friend if she had romances with movie crews in Hollywood. Her friend replies that she did, and that she dated a grip, a gaffer and a best boy, but she still doesn't know what any of them did.
This is much safer. After Lynne's problems with dogs, she has not only decided to exercise in a jogging hot spot but has taken a friend along in the unlikely event that the dog comes back.
Lynne's friend has recently been to Hollywood. It is not known what the purpose of her trip was, business or pleasure, but either way it makes her a complete hussy. If she was there for a holiday she managed to sneak onto a film set and have liaisons with three separate members of the crew. If it was business then she is probably earning a reputation of sleeping her way through the crew. Not very professional.
If this woman had actually paid attention to the men she was dating and asked them questions she would know that a grip is responsible for mounting cameras, and possibly lighting, a gaffer is the head of the electrical department and a best boy is an assistant to either one. The order in which these romances happened is unclear, but because of their close proximity on the set, it is likely that it caused ructions, ultimately leading to one of them being fired.