That sounds familiar. I feel like there may be a branch very early in the chick for a dick thread where Jon wishes to switch places with Karyn. I'm having trouble finding it right now but it could be a branching off point for you. I think one branch of it had him becoming Karyn's vagina, and another had Jon being Karyn's genitals, but Jon still felt Karyn as if she was his penis... something like that... It was way back before ekempo's conttibutions that really set the tone for that arch.
There is also a completely different branch where Karyn and Jon both become Sarah's vaginas.
