Maybe it shouldn't be surprising that adults associate sensuality with babyhood. Infants are pure, shameless id, little bundles of unregulated desires, oblivious to social prohibitions. Sometimes, when a baby nurses, her eyes roll back into her head and she drops into a smiling sleep, still attached to the breast. Milk bliss, a friend calls it. Sex, you figure, is adults' way of trying to regain that state.
Toddlers are more complicated than infants.
The rules make the world navigable, safer, easier to understand. Toddler humor is about flouting rules. The humor lies in the absurdity. It'll happen when it happens. I'm not worried about Ben.