You can't tell from your position, nestled deep in the cup of Mary Lynn's bra, why they did it. Maybe Amber was turned on by her tiny husband rubbing against her cunt. Maybe Mary Lynn had a secret attraction to Amber that had been suppressed for years. Maybe they were both turned on by their size and newfound sense of power. No matter what the reason, when Amber and Mary Lynn finally took the chance to look around at the shrunken world around them, they then looked deep into each other's eyes. And then started making out.
From your perspective, you mostly notice when their chests slam together, momentarily knocking the wind out of you. But they keep going at it with lust, and you just stay hidden, hoping not to be seen. So you don't see them rubbing their hands all over each other's bodies. You don't see Mary Lynn slide her finger along Amber's panties, inadvertently shoving Clyde deeper inside his wife's pussy. And you'd have been terrified if you'd seen Amber taking her bra off. If Mary Lynn decides to do the same thing, you're toast.
In fact, you're almost toast when Mary Lynn's passion gets the better of her, and she slams Amber to the ground. As the women writhe over each other, all you can feel is being tossed around left and right. But you hold on, and you're still okay when the two giantesses break away from each other. They haven't said anything in a few minutes, but the words you hear next are unmistakable.