Rin's tail was sensitive. Yukio knew this. But they'd never acknowledged this in the bedroom. At least, until it fell onto Yukio's abdomen as they lay in bed one night, and Yukio's hand reached down and stroked it, feeling the softness of the fur beneath his fingertips.
"Mmm," Rin moaned in his sleep, tail and cock twitching. Blood flowed into each, and both stiffened.
Groggily, Yukio squeezed, and the shock of that touch was enough to wake Rin.
They were naked – they always slept naked together after fucking – and Yukio could see his brother's cock hard in the moonlight streaming through the bedroom window.
"Oh, Rin," Yukio breathed. "My lovely, gorgeous brother."
Rin's eyes snapped open as Yukio absently stroked his tail, which twitched in his hand. His cock strained with each of Yukio's strokes, getting harder with each one, until it was fully erect, seemingly ready for release.
Then, instinctively, Rin's tail slipped through his brother's grasp and wrapped gently around Yukio's cock, stroking him from base to tip with steady movements.
"Oh, my God," Yukio breathed. "What-"
This was a double-edged sword. Not only was Yukio getting jerked off, but Rin's sensitive tail was getting stimulation as well, which increased when he felt the touch of Yukio's hand ghosting over it as it stroked him. When the movements became too quick – Yukio wanted this to last – Yukio gently gripped his brother's tailed and slowed its movements, guiding it carefully up and down.
"Make it last," he whispered, his breath hitching at the end of the request as Rin's tail tightened ever so slightly around the head of his cock, and the tip of it brushed against its tip. "Oh, Rin. Fuck."
"Mmm," Rin mumbled. "I know." When Yukio's hand fell to his side, Rin pleaded, "Touch it, Yuki. Please."
Yukio sucked in a startled breath, loving the sound of Rin's words, and slid his hand along the tail, backwards, until his hand was between Rin's legs and nearly at its base. Once there, Yukio gently groped his brother's balls in his hand and squeezed them lightly, making Rin's hips jerk forward. Then, his fingers fluttered back over the base of the tail, landing at his brother's entrance.
"Y-" Rin started, but his brother's name was strangled in his throat as he gasped in response to Yukio's fingertips gently pressing into his hole.
Yukio pulled them out slowly, then squeezed the base of Rin's tail, pinching it lightly where it met his body.
"Ah, fuck," Rin moaned. "Feels so-" Yukio stopped his words once again as he pushed his fingers back inside.
When he rolled over, kneeling between Rin's legs, his brother's eyes went wide. They opened even wider when Yukio used one hand to spread Rin's asshole and the other to squeeze the base of his tail.
"Stroke it," Rin begged, his voice a strangled cry. "P-Please, Yuki."
His brother obeyed, stroking his hand from the base of the tail halfway down to where the tail continued to steadily stroke his member. The monotonous rhythm was allowing Yukio's arousal to wear off. He needed a variation in speed and pressure to cum. Knowing this, and sensing that Yukio was no longer as aroused by the touch, Rin slid his coiled tail up and down his brother's length a great deal faster, suddenly pumping him in wild, frantic jerks, making Yukio gasp and jerk his hips forward into the grip of Rin's soft tail.
Once he'd regained control, Yukio stroked his own hand up and down the exposed portion of Rin's tail, savoring the sensation of fur beneath his fingertips. Knowing that Rin also needed regular variation in stimulation, Yukio squeezed and pinched lightly at random, sometimes near the middle of his tail, sometimes at the base. Each time his fingertips grew dangerously close to where the tail met his body, Rin's hips jerked up, his cock throbbing.
Yukio's cock was, of course, aching as well, and the outer veins of the organ pulsed hard beneath the strokes of Rin's tail. The movements then slowed and became steady once more, causing Yukio to let out a low groan as his tail squeezed hard but moved at a painful pace from the base to the head. Then, the spiral of Rin's tail loosened and spread out over his cock, instead of coiling close together, then squeezed and released the length over and over, making his brother's penis throb harder from the sudden change in stimulation.
"Yuki," Rin gasped, as Yukio's legs started to shake. "Are you gonna-"
"Yes. Rin, yes. I'm gonna cum."
"Wait," his brother begged. "Don't cum yet. I want… Ah! Yuki!"
His cries were elicited by the firm squeeze of Yukio's hand right at the base of his tail. It was so hard it hurt, but the intense burst of pressure sent Rin into shock.
"Fuck. Yuki!"
He was too close to stop. Too ready to cum. He was bursting, his balls ready to release their seed through his penis and onto Yukio's warm skin.
"Gonna… Gonna-" Rin gasped, straining to rock his tail harder into his brother's grip.
But Yukio loosened the grip and taunted, "Don't cum yet."
Screaming in agony as Yukio fully let go of his tail, Rin thrashed beneath him, his own tail stopping its movements as well.
"Slow?" Yukio asked, stroking his brother's cheek.
Once he'd caught his breath and released his feelings of spite for Yukio's torture, Rin nodded his head slowly, conceding breathlessly, "Okay. Slow."
Yukio gently unraveled Rin's tail from his cock, rubbing it down its length as he pulled it away, and gripped the very tip of it. Then, he gently brushed the furry tip of the tail against the tip of his member, shuddering at the sensation. Slowly, his free hand found its way back to the base of the tail, right near Rin's puckering hole, and he stroked it lightly, and only with his fingertips. This made Rin moan in agony again, wanting full stimulation but receiving only tormenting teases of his brother's careful touch.
"Oh, yes," Yukio sighed, as the tip of Rin's tail stroked his penis from head to base, over and over, repeating the movement at varied speeds. "Rin, yes."
Rin whimpered his brother's name and lifted his hips, pushing his tail into his brother's palm. But Yukio quickly lifted the tail, then brushed the base with his fingertips again, this time holding the bottom half still. It nearly tickled, but the fluttering sensation of Yukio's touch on his fur made Rin blind with want.
"Yuki, please. I need you."
"Need me how, brother?"
Swallowing hard, Rin confessed, "Inside me."
With a nod, Yukio quickly grabbed the tube of lubricant from the bedside table and poured some onto his hand, then covered his length in its slickness. Yukio used the next dollop of lubricant to moisten the tightness of his brother's entrance, and when his fingertips pressed in once again, Rin gasped and whimpered at the touch and heat.
"Yuki."
"Yes, love."
"Need you."
"I know, baby boy. I know."
Offering Rin's tail a long, steady stroke that made Rin's whole body convulse, Yukio then flipped his brother onto his back and positioned himself behind the young man, cock still pulsing and ready.
"Are you ready?" Yukio asked, stroking Rin's back slowly, from his shoulder blades down to his tail.
When his brother touched its base, Rin gasped and shuddered again, nodding quickly, and Yukio took his cue at once, lifting Rin's tail out of the way and pushing himself slowly into his hole.
"Oh, God," Rin groaned, his head falling to the pillow as he pushed his ass back against his brother's crotch. Then, when Yukio began to move back, Rin moaned, "Just like that, Yuki."
"Yeah?" his brother whispered, speeding up his thrusts but keeping them steady.
Rin simply whimpered loudly – desperately – in response, continuing to push back to meet every one of his brother's movements.
"Do you think you can cum without me touching your dick?" Yukio asked, voice husky and low as he dragged his nails down his brother's back.
"I… I d-don't know," Rin stammered, rocked by each of Yukio's thrusts.
"Let's try."
"But I… I need-"
"No. You don't. I'll show you."
His brother nearly screamed when Yukio carefully dragged his nails through the fur of his tail, from the base all the way to the tuft of fur at the end. He also nearly collapsed. But he managed to stay upright, his ass lifted in the air to give his brother better access to what they both needed. Yukio's hand then began to work magic as it pumped Rin's tail, again and again, his touch light but fast. Just as he began to climb towards his peak, Rin's tail, with a mind of its own, wrapped around behind his brother and slipped between his thighs, the fur rubbing Yukio's balls from behind.
"Oh, God. What are you doing?" Yukio groaned, his thrusts inside of his brother slowing to a pressured grinding motion.
Instead of responding, Rin grabbed the bottle of lube, slicked the tuft of fur at the end of his tail, and continued to let it do what it wanted, which was to wrap around behind Yukio once again. This time, it pressed itself between Yukio's ass cheeks and rubbed against his puckered hole.
"R-Rin," he gasped, legs suddenly shaking, his grinding slowing to a stop.
"Y-Yes, brother."
"I… Ah!"
And then, the tail was inside him, tickling the walls of his anus, pushing deeper and deeper, earning low, guttural moans from Yukio's throat.
"Brother," Rin said. "Don't stop."
Yukio had completely forgotten to move, blinded by the pleasure of the organ inside him. Ashamed of this, ashamed that he'd forgotten his own brother's pleasure, he abruptly began to thrust hard and fast, which made Rin gasp and cry out. As he moved, Rin's tail matched the paced and pressure, which drove Yukio wild. When he slowed, so did the tail inside him. When he thrust harder, so did the tail inside him. But Yukio soon became overwhelmed by the double stimulation, and he felt as though he might actually black out. He managed to stay present, but he needed a moment to steady himself, so he pushed back in slowly, the veins of his cock pulsing and throbbing hard, and held the position. Rin found that he loved this, the feeling of being completely and totally filled with his brother's hard length, feeling all of him inside. Nothing could be better. Nothing could be more intoxicating.
But Rin soon found out that this was not true, when his tail's sudden, eager pressure on Yukio's prostate caused his brother to push against him even harder. Without so much as one more thrust, Yukio's body spasmed, and he grabbed the base of Rin's tail instinctively, both crying out loudly from the pleasure.
Yukio screamed, "Rin! Fuck!"
"Yuki, baby. Please. Please. Oh, God."
Each further aroused by the other's desperate moans, Rin and Yukio both came hard, and Rin was amazed at the amount of cum that erupted from the head of his own cock and soaked the bed sheets. Yukio was then amazed by how skilled Rin's tail was at rocking his body with intense pleasure. The tip of his tail was pressed firmly against Yukio's prostate and continued to rub him there, in steady circles, nearly vibrating against his most sensitive organ, even as Yukio stimulated the tail's base. This drew out each of their orgasms, to the point where they felt they'd never end. Bathed in bliss, Yukio filled his brother with his cum, making Rin scream his name as he felt the hot seed coating his own insides.
They both pulled out slowly, and their bodies twitched from the added stimulation as they came down from their high. Once Rin's tail was completely out, Rin stroked its fur, soaked with his brother's cum, over Yukio's chest, teasing his perked nipples.
"Rin," Yukio said, sucking in a sharp breath. "Jesus."
"Jesus isn't here right now, Yuki. Just the son of Satan."