The Ark is a socially acceptable way of animating the fact that they are sexual partners and gives a clever explanation to the fact that the clothing throughout the animation suggests that it is raining. The story starts by making it look like a parlor trick for free drinks then develops into what looks like a sadistic prank but it ends up finding an endearing resolution that puts everything right. Let the animation speak for itself, pigeon-holing is a fool's errand.