The mine was quiet except for the wet slap of flesh on flesh. Brakk, broad as a boulder and thick between his thighs, had his sister pinned against the rough stone wall. Her name was Thora, shorter even than him, with heavy tits that swayed as he drove his cock into her from behind.
"Fuck, sis, you're tighter than the new tunnel we dug last week," Brakk growled. He grabbed her hips, fingers digging into the soft flesh above her ass, and slammed in harder.
Thora moaned, pushing back to take every inch of his fat dwarf prick. Her cunt was soaked, dripping down his balls with every thrust.
They'd been at it since their parents left for the upper halls. Alone in the family cavern, the taboo heat always flared fast. Brakk had bent her over the anvil first, licking her slick folds until she begged. Now he was pounding her standing, his beard scraping her shoulder as he leaned in.
"Harder, brother," Thora panted. "Fill your sister's cunt like you always do." She reached back, spreading her ass cheeks wider so he could watch his shaft disappear into her. The sight made Brakk grunt and speed up, his heavy sack slapping her clit.
He pulled out suddenly, spun her around, and lifted her onto the wooden table. Her legs wrapped around his waist as he shoved back inside. Sweat ran down his chest hair, mixing with the juices coating his cock. Thora clawed at his back, urging him deeper.
Brakk fucked her with short, brutal strokes, the table creaking under them. "Gonna breed this dwarf pussy," he snarled. "Gonna pump my seed right where it belongs." Thora's eyes rolled back as she came, her walls clamping down and milking him. He followed seconds later, roaring as thick ropes of cum flooded her womb.
They didn't stop there. After catching his breath, Brakk sat on the bench and pulled Thora onto his lap. She rode him slow at first, grinding her cum-slick pussy on his still-hard dick. He sucked her nipples, biting just enough to make her yelp and clench. Soon she was bouncing hard, tits flying, while he fingered her ass.
"More," she demanded. Brakk stood again, carrying her impaled on his cock to the bed furs. He laid her down and flipped her onto all fours, mounting her like a beast. His thrusts shook her whole body, the wet sounds echoing off the stone. When he came again, he pulled out and painted her ass and lower back with the rest of his load.
They lay tangled afterward, his fingers idly stroking her swollen slit. "Same time tomorrow?" Thora asked, voice hoarse. Brakk nodded, already half-hard again at the thought of their next secret session deep in the mountain.
