Having one or more lesbians as your keyholder certainly would be challenging. Even worse if the guy found that seeing them together was a total turn-on. "Hey, chastity boy, come into the bedroom with us. We want to show you a new game we learned to play with each other."
I like the idea of lesbians fascinated by their hold over a man. And the fact that they have discovered that even though they get nothing out of having SEX with a man, that does not preclude their obtaining pleasure from TORMENTING a man.