Seiji straightened.
The taste of Yumi's milk was still on his lips, and the amulet buzzed against his chest like a second heart.
Yumi's eyes followed him with wonder. Like they were seeing a new world.
A world he had just created for her.
"Seiji…"
That was all she breathed, but they way she did it was worth a thousand words for Seiji.
Then her gaze drifted down and flickered. Right in front of her was the straining bulge in Seiji's pants. Hard and undeniable.
Her nostrils flared.
The old Yumi most likely would have flushed and looked away. The new Yumi saw a problem she was born to solve.
"Well," she whispered. "You helped me. So it's my turn."
She slowly reached up, her fingers trembling slightly. She freed her brother's cock, her touch sending a sharp jolt of electricity up Seiji's spine.
"I can't just leave you like this," she murmured.
Her fingers circled the base, her thumb rubbing over the head with a skilled precision that made his hips jerk.
"It's so big…" she muttered before she caught herself.
What is she saying? Is she comparing me to her husband?
Seiji hardened even more from the thought.
Yumi glanced up at him, her eyes dark and deep. "Never mind." She began to stroke him slowly.
"Your body reacts so honestly," she whispered, a small, triumphant smile on her lips. "I like it."
Seiji's cock was right at breast level. Yumi moistened two of her fingers in her mouth, then spread the saliva onto her swollen nipple, making it gleam.
"You made me feel so good," she whispered, her voice loud in the silent room. "Let me return the favor."
Seiji heard his own whimper as Yumi began to rub his cock against her nipple in tight, slow circles. The sensation was unlike anything he had ever felt in his life.
Holy crap! The amulet is even more powerful than I thought!
He didn't just bring Yumi to orgasm.
Her body wasn't just responding to him; it was now hungry to serve him. Her pleasure wasn't the goal; it was the key. To their union. To happiness. To worship.
He unlocked her breasts, which fed her child, to be a source of pleasure. First, for her. And now, for him. This wasn't simply a reward.
It was an anointing.
"Oh, sis!" Seiji moaned loudly, making her smile.
"You like this?"
"Yes," he groaned.
She flicked her nipple repeatedly with the head of his cock, gasping softly with each contact. "Did you say a bad word?" she moaned, mockery and seduction mixed in her tone.
"No…" He was a well-behaved boy.
She circled the nipple again, a little faster. "Well, you should. You're having sex, so you can say bad words, you know?"
Seiji's mind went blank, his knees twitching. "Fuck…" he blurted.
"I can't hear you, brother?" she cooed.
"Fuck!" Seiji groaned louder, his voice breaking. "I like it so much…"
Yumi watched his face, fascinated by his suffering, dragging her nipple slowly along his entire length. "It's so long," she repeated again to herself.
She increased the speed again, and Seiji's whole body tensed like a wire pulled to its breaking point.
"Too much… I can't hold it like this…"
"That's okay," Yumi purred. "Then cum. You can cum on my boobs."
Seiji's eyes were fixed on his sister's breasts as she began to stroke him faster. The familiar sensation at the base of his spine hit him, his balls tightening. But this was a million times better than using his own hand, so his eyes simply rolled back in his head.
"Cum!" Yumi urged him.
Grabbing onto her shoulders for balance, Seiji groaned and started shooting ropy strands of cum right onto Yumi's breasts.
Yumi's eyes gleamed with a satisfaction as she circled his cock around her swollen nipple, hot white liquid dripping all over her.
When Seiji's cock finally stopped contracting, he opened his eyes again.
"That was AWESOME," he said.
"It was." Yumi slowly rubbed his cum into her skin, watching it get watery and slide down her body. "First you helped me with my milk, and then I helped you with yours." She raised her eyes, looking impressed. "You also had too much." She traced the beads running down her belly. "Look, it's all over my body."
Seiji felt a tingling pride at the back of his head. He couldn't take his eyes off her cum-covered skin.
She was right: it was his cum, and it was all over his sister's body.
He had marked her.
And she was wearing his mark like a crown.