A Large Dildo (Anal)

The scientist takes his cutting tool and carefully cuts out a square of the Zero Suit exposing her pert little asshole. The engineer always believed the most tempting part of a woman was not just her ass but her asshole too. He had spent many hours alone in his room jacking off to women stretching their hole out with giant dildos modeled after aliens of all sorts. And now he has the perfect ass presented to him at his mercy. He opens his mouth as he begins licking her asshole and worming his tongue inside. Samus shudders at the foreign feeling. While she had plenty of stress relieving one night stands she had never tried anal. She just always thought of it as dirty and never experimented with it.

Samus begs "No stop, now!" To her surprise the man actually does. "Okay now let me go. OW!" She was spanked hard as the man speaks "No, now tell me why I should stop?"

Samus is stubborn and refuses to answer the question but feels a spank and a finger enter her ass. This gets her talking. "Stop, okay I'll tell you. I never played with my ass. If you're going to fuck me just use my pussy like you're supposed to.".

The man doesn't care about that answer, if he wants her ass he will take it and she can't stop him. But something about the voice was familiar. He checks the stations log as he realizes the woman at his mercy is the famously beautiful bounty hunter Samus Aran. One of the man's favorite smut movies was a a cosplayer dressed as Samus getting fucked and having her asshole stretched after being captured by space pirates. He'd cum at the thought of taking the pirates place as the one abusing her rosebud. And now not only can he live that fantasy he sees she even has the upgrade port installed on her. He orders the AI to send some chips his way. He puts them on the nanomachines as they carry the chips through the tight vent and insert them into her neck. Samus feels warmth in her butt unaware she was upgraded. Now her ass will remain naturally tight but can be stretched well above normal human levels and will never tear and only feel heightened pleasure with no pain. He tests this by making the nanomachines form a silicone dildo measuring 18 inches long and a girth of 10 inches and to humiliate Samus more it's shaped after the cock of her enemy, the space dragon Ridley.

The man also had a large bottle of lube delivered as he begins covering the dildo in it. He holds the heavy toy in his hands as he lines the tip up. Samus feels something prod her hole. "Hey I said stop! Don't touch my asshole, you asshole!". The man grins as he begins pushing as the bulbous tip forces it's way in. Samus tries clenching her cheeks to keep it out but can't stop it as the head of the toy begins slowly stretching the hole. Samus lets out an involuntary moan as she wonders how it feels so good. The engineer works the flared head in as the ribbed shaft begins passing through her ring. He pulls and pushes the toy in and out as he fucks her asshole with it. The ribbed texture pulling on her sphincter. He sees her pussy getting wet and Samus wishes she could finger herself to relieve the pleasure building in her colon.

Samus just groans in pleasure as the dildo is being thrusted into her an entire foot before being pulled back out. The engineer decides it's time to go all the way. The dildo ends with a bulbous knot that thins out before the flanged end will keep it inside her. He pushes it in as the bulb presses on the ring stretching it more than her asshole has ever been stretched. Samus eyes shut as she screams in pleasure feeling her stretched beyond what she thought was her limit. With a final push she squirts as her butt finally swallows the plug and closes with the flanged base keeping it from going further in and the bulb keeping her from pushing it out.

The engineer is happy with his work but his erect cock demands attention. He has a wicked idea and sends new instructions to the nanomachines in the dildo. The machines hollow out the end that is sticking out as he sees a fleshlight of an asshole appear in the dildo. He wastes no time in lining himself up and thrusts inside. His movement thrusting the full length of the dildo further inside her. He thrusts with wild abandon pushing and pulling the large alien dragon cock in Samus bringing her through more and more orgasms. He cums into the toy as it's mechanism makes the dildo shoot his cum out it's tip filling her. Samus barely notices as her mind has permanently changed her into a butt slut no longer wanting anything in her pussy, just her asshole.