Conclusion
I feel that Penny's theory about what turns an exhibitionist on while that person does his or her thing (displaying themself in some form of sexual activity to an eager audience) makes a great deal of sense in her case.
She is a girl who obviously learned to love sex very early in life. At first, she had to take the voyeur route, but as her husband learned what satisfied her more, he soon taught her to go with her own feelings. While she was going through that stage, Penny learned how truly sensational the sexual orgasm could be.
The exhibitonist stage followed shortly, for one of the things that added to Penny's orgasm was knowing how much her partner was getting turned on. If the partner turned out to be a voyeur, as in the case of Harry and then John, it only added to her pleasure even more. She actually feels sexual thrills knowing that someone who watches her is getting turned on. Sometimes, however, I wonder how it would work for the exhibitionist or the voyeur watching her did not get turned on. Would it be a turn on for the exhibitionist, or not? Perhaps one day, Penny will experience such a situation.