You let her have this one, but write a few complementary rules

Old Rule: Men may touch, taste, suck, or fuck any exposed part of a woman's body when she's in public, but only using parts of his own body which he is allowed to expose.

You deliberately leave lesbians out of the fun with Frankie in mind; you like the idea of her keeping her hands to herself with all this tempting flesh around her. You also don't want to see any more dicks around than necessary, so you give guys a chance to get some quick relief and put it right back in their pants:

Old Rule: A man may take his penis out wherever he likes, but only if and when he's fully erect. If he looses his erection for any reason, he must put it away as soon as possible.

You drop to your knees and run your tongue up the inside of Frankie's thick thighs. You start at her knee, trailing up as close as possible without getting her pubes in your mouth, before doing the same thing on the other side. It's not much of a tease, but it's enough to make her pussy lips glisten. They catch the fluorescent lights, even through her dense bush, drawing the eye down from her impressive rack. You know it won't last unless someone else decides to play with her, but for now at least her sneaky little workaround isn't really working at all.

You give her a playful swat on the bum -- which jiggles beautifully -- and send her on her way.