The emerald and a device

Rouge reached inside the safe and removed her prize, a yellow Chaos Emerald. She admired it for a moment, how it glimmered in the light and had a faint glow. It was glorious.

"Alright, you got what you wanted, right?" Tails exclaimed, his expression appearing usually nervous to Rouge.

She was prepared to just take off, but suddenly her thieving instincts got the better of her. No doubt Tails had a few more valuables in his safe, and what better time to make off with them than now?

She began peeking back into his safe.

"H-hey! What are you doing?!" he demanded, "You already got what you wanted, right?!"

Rouge ignored him as she looked deeper inside, only to be met with a surprising sight.

"What have we here?!~" she asked, pulling something out of the safe.

It was a harness with black straps that wrapped around to a crotch piece, but what made this object interesting to her was the phallic object attached to the crotch. It was clearly a dildo, a big one at that, molded from a kind of silicon, colored a deep blue, and branded with the label 'Sonic model V1' in bold white letters on the side.

"Tails!~" she giggled, "I never knew you were into this kind of stuff.~"

"T-that's a p-personal experiment! Put that back!" he blushed.

"I'm sure it's very personal," she said, reading the side of the dildo, "So does Sonic know you named a dildo after him?"

"I said, put it back!!!" Tails blushed, struggling to escape his bindings.

Rouge, enjoying teasing the little fox, began strapping the device to her waist. Upon closer inspection, the phallus was not only made from silicon but also appeared somewhat mechanical.

"How do I look?" she asked, taking hold of the dildo and playfully wiggling it back and forth as if it were her own penis.

"Stop that!" he demanded, "That's a very sensitive piece of technology! It's meant to test the power production of Chaos Emeralds and nothing else!"

Rouge observed the length of the dildo and noticed a spot that looked like it would fit an emerald just at the base. A devilish smile sprouted on her face and she approached the helpless fox.

"H-hey! What are you doing?!" He asked as she flipped him over onto his stomach.

"Well, I'm really curious how this thing works,~" she said, approaching his backside.

He tried covering his rear with his tails, but Rouge effortlessly pushed them away giving her a good view of his backside.

"I never noticed how big your butt was, fox boy,~" Rouge teased, "Just the right size for a dildo.~"

Tails could feel beads of sweat beginning to form on his brow as she aligned the dildo with his asshole. Sliding the emerald into its slot at the base of the dildo, Tails' body tensed as he felt the tip of the now vibrating dildo pressed against the ring of his asshole.

"W-wait! That machine is untested!" he said in a last-ditch effort.

Rouge chuckled, "Well, there's no better time to test it than now!"

She slid the dildo inside and he let out a massive moan. Exhilaration ran through his body as the dildo filled his insides. He could hardly control his breath as his penis started twitching faster.

"That wasn't so bad, was it?" Rouge said, giving his ass a rub.

Rouge proceeded to pull and press her hips against him in a circular motion, each movement seeming to bring out more aroused noises from the fox.

Tails's toes curled with each thrust. He could feel his entire body vibrating, but the brunt of it was squarely focused on his prostate. The euphoria emanated through him, leaving him barely able to think let alone fight back.

"I-I-I'm g-gonna c-c-c-c-cum!" Tails stammered.

"Good! Let it all out!~"

And with one swift thrust a rope of cum shot out from Tails' cock.

"AAAaaahhh!!!~" he moaned, as cum continued to squirt out.

Rouge finally pulled the dildo out of his anus, allowing him to fully collapse onto the floor.

"Well, I'd say that was a successful test run," she smiled, unbuckling the strapon and pulling out the emerald.

She tossed the contraption next to Tails and strutted towards the exit with her prize.

"We'll need to do this again sometime. Give me a call if you find any more emeralds.~"

Leaving the fox boy alone in his workshop, he could only lay there in the afterglow of his euphoria. If someone found him they would certainly have questions as to why he was tied up and lying next to a dildo, but for the time being he did not think about that. He just went to sleep, a big dumb smile on his face.