Irene removed the cock ring with a smug flourish, and Sherlock's body plunged his mind past the point of no return.

His eyes rolled back in his head and his long white form went rigid as one orgasm after another blasted through him. Having found the threshold of pleasure, he clung to it fiercely, determined to hang on, relishing the way his body quaked through a seemingly endless cycle of contractions, surges, and ecstasy. Touching himself had never been like this, never ripped control from him, never made him beg for "Mercy" when he really meant "More."

Irene stroked the hair off his forehead as the tremors continued. "That's it, dear boy. Come for us. So sweet…. And this is only the beginning."

Mycroft put it more bluntly. As he bit bruises into his brother's sweaty neck, he said in a deep, menacing growl, "I'll worry about you more than ever now, Sherlock. You've always been a slave to your impulses, and now you've found a new obsession you won't be able to conceal. Men will look at you and know… know what a slut you are."

Hearing the word 'slut' fall out of his brother's normally dignified mouth, Sherlock shivered and climaxed a fourth time. Although blindfolded, he knew that Mycroft's chest and belly had to be dripping with his sperm. "Yes," he gasped.

"You'll want it all the time. Mark my words, little brother. If a decent-looking fellow so much as smiles at you, you'll be on your knees or presenting your arse. I'll be taking extreme measures to protect you from yourself. Irene has so many delightful toys that can keep your body limited to my use alone. Would you like that?"

"Yes!" Sherlock cried. He meant it. It couldn't be any better than this. It couldn't. Repeated orgasms, the pain that sharpened his pleasure… only Mycroft could ever know him well enough to accomplish this type of magic.

Mycroft would have said more, but that searing hot litany was interrupted by his own orgasm. "Oh, Christ, oh fuck! Sherlock!" he cried as he did one final dive into his brother's reddened hole and corkscrewed his hips. Sherlock felt a soft warmth spray his insides and trickle lightly through the seal where their bodies joined. Then Mycroft collapsed onto him and relaxed, chest heaving and fingers caressing Sherlock's hair.

The younger Holmes laid there, dazed and sated. He felt Irene remove the ties from his wrists before briskly massaging them and positioning them gently at his sides. He immediately raised his arms and wrapped them around Mycroft. When he felt the sweat that had soaked through the dress shirt, he smiled. It had been ages since he'd witnessed his older brother coming so undone, and Sherlock felt a surge of affection for the first time since adulthood had hardened both of them.

"Thank you," he whispered.

Mycroft pulled the blindfold away from his eyes, allowing Sherlock to see it all: the dimly lit and luxuriously furnished bedroom, his brother's beaming face, Irene's robed form as she reclined next to them. When he looked at her covered body in clear confusion, she kissed his nose and beamed.

"Delicious as you both looked, I only play with boys. I don't have sex with them."

"But you and Mycroft-"

She traced his kiss-swollen lips with one blood-red fingernail. "Mind-fucking only."

Mycroft rolled off of his brother but remained against his side, one arm and one leg keeping Sherlock 'prisoner'. The younger man reached down to clasp the trouser-covered knee, loving how Mycroft's being dressed made him feel even more naked and vulnerable. His cock twitched in interest, something Mycroft noticed.

"Oh, Sherlock," he sighed. "Irene, I believe we've created the proverbial monster."

"Well, you know what has to be done to monsters." She tweaked Sherlock's nipples without taking her eyes off his crotch. "They must be put away for their own safety."

In the morning, they put what Irene called a M.C.D. ("Male chastity device," Mycroft translated.) on him. When they showed it to him, he was instantly intrigued by its design: three interlocking pieces made of medical grade polycarbonate material that fit together like a puzzle. It covered his penis and had a vented tip, making it both restrictive and accommodating.

"You'll be able to urinate while wearing it, but not wank," Irene said fondly as she secured the device with a brass padlock. When she placed the key in Mycroft's open palm, Sherlock felt his stomach flutter.

My brother. My lover.

"And now your key holder," the elder Holmes declared, finishing that thought for him. After tucking the gleaming object into his trouser pocket- where it would brush heavily against his crotch when he moved- Mycroft took Sherlock by the shoulders and guided him into a firm backwards embrace. "Don't worry. I won't let you suffer. At least not much."

Sherlock was surprised by his own reaction. He'd always resented Mycroft's attempts to interfere with his freedom and control him. But the thought of his brother holding the literal key to –in other words, supplying- his pleasure was both hot and liberating. He leaned his head back against Mycroft's shoulder and brushed their cheeks together, relishing the contact. He'd never have imagined that his icy older sibling could feel so warm. So human.

"I'll be watching you more than before," Mycroft murmured.

And for the first time, Sherlock did not mind.