Imagine a girl, maybe a bunny, or cat, or human, about 12, sitting on a much larger male's lap, eagerly riding his cock, facing forward.

His massive right forearm is across her chest, hand cupping a breast (large for her age), his left is on her waist holding her secure; conversely, her right hand is resting on his forearm, her left reaching back to steady her against his hip bone.

She is starting to cum, eyes closed, her chest having cutely, her hips bucking as she moves up and down; his cock large enough to make a subtle bulge in her flat belly, the position showing that she never comes near to pulling off it.

After a cycle or two of that, his right hand moves up to caress her left cheek (the one on her face, pervert!), making her smile as it moves down to cup her chin. His left hand starts moving too, before the right one even touches her face, coming to rest over the top of her head; the heel of his hand is just above her temple, his left forearm continuing to rise until it's horizontal, his upper arms starting to bulge as he prepares.

All of this takes maybe a second while the girl is still happily moving in the afterthroes of cumming, unsuspecting, sighing (visibly exhaling) and opening her eyes with a sated look.

But as soon as he's ready, without any sort of pause, he pushes with both hands, wrenching her chin up and left, the top of her head the other way, breaking her neck instantly, her eyes and mouth opening in shock. This happens to be at a the top point of a bounce, and he keeps her there, twitching and bucking on his cock for a single beat until his cum starts running down his cock. (Her breathing and heartbeat has stopped instantly, and the bucking is just muscles running amuck without signals from her brain).

Then he leisurely turns her head upright again, supporting her weight by his right hand under her chin, and lets her down until she hilts his cock, his left hand finding her breast and pinching her stiff nipple; as he leans her limp body back towards his chest, she gives a last twitch, and we fade out as his cum dribbles out of her stretched sex and over his balls.