Transformers Movie-verse, Sam/Megatron, tentacle rape
In a way it was a relief to have his mouth filled. If he couldn't talk intelligibly, he couldn't say stupid stuff like 'There's nothing worse you could do to me, Megatron.' Because apparently saying things like that to Megatron made him want to prove you wrong.
He was clinging to Megatron's hand in a death-grip; at first he'd done it because if Megatron dropped him, he'd die, but now he wasn't sure he could let go if he wanted. His mouth was stretched around a mass of writhing, whipcord tentacles, tasting of plastic and electricity and yes, diesel, and once Megatron was finished shredding his clothes off his body Sam knew where the second mass was going to go. He hunched, trying to protect himself, and Megatron growled and forced his ass back up with a hard claw between his legs. Sam gasped at that press against his manhood, horribly warm, and couldn't help a boneless writhe against the metal.
"So impatient," Megatron purred, and Sam whined an unintelligible plea around the tentacles in his mouth. Megatron laughed, an altogether malevolent sound, and his bladed hands tightened around Sam as the wicked tentacles forced themselves one by one into his back passage. Stars exploded behind Sam's eyes, dripping Cybertronian glyphs and ancient visions, and he wailed and thrust back against Megatron's hand. More pain, more stretch, more fullness; Sam groaned for it all and knew Megatron had won.
It wasn't fair, he found himself thinking. Oh, Optimus, it wasn't fair.