Brotherly Love (Blackcest)
"Ah! Yes Sirius! Faster!" Regulus cried out to his brother as his body rubbed against the sheets. Their parents weren't in the house, Kreacher was out somewhere probably stalking some poor female house elf and their cousins, Narcissa and Bellatrix, were upstairs sleeping or doing something quiet.
Sirius obeyed his brother and quickened his thrusts. It was just an experiment; Regulus helping Sirius find out if he liked girls or swung the other way and likewise for the other.
"F-fuck Sirius, I'm close!" he whined as his brother worked in and out of him. Suddenly the older boy pulled out. "H-huh?" the younger asked in confusion. "Get up we're switching." he explained already going on his back. The younger sat up without a word. "So am I gonna...?" he let the question hang in the air. "No silly. You're gonna ride me." Regulus wrinkled his nose. "I'll explain later." he guided his brother so that he hovered over his member. His sibling glanced nervously at him, the emotion displayed on his face.
The two boys almost gasped aloud at the sensation each felt. For Sirius, it was being inside his brother; for Regulus, it was Sirius inside of him. After a while the younger Black began to squirm which prompted Padfoot to start lifting his brother. "Oh Merlin." he breathed as he felt the cold air tickle the base of his cock before his brother's warmth wrapped around him again. Said brother covered his eyes with his hand, thoroughly embarrassed. "Damnit, you're a heavy kid." Sirius chuckled. "Don't make fun of me." he snapped as his brother accidently slammed him down roughly. "Oops. Sorry." he apologized. His little brother glared at him through his fingers.
Next two hours were spent silently, except for the occasional gasp or moan. The younger Black soon got the idea and began to move by himself although Sirius occasionally helped. "Ah~ You're so good." the older Black moaned bucking involuntarily. "Siri, I'm close." he whimpered. Suddenly he felt something warm fill him. He glanced at his brother who was leaning back, his chest heaving. "Um, Sirius... I think I'm dying." his brother looked at him with an confused expression. "What?" the younger boy's eyes water. "I'm dying!" his brother pulled out with concern. "What do you mean dying?!" he yelled. "I felt something come out of you and go inside me!" he sounded hysterical. He anxiously looked in between the other boy's legs and relief washed other him. He ruffled his little brother's hair. "That's my cum silly." "Your WHAT!?" "My cum. It's what I make when sex is good." Regulus blushed. "Oh." he looked at his own chest which had white stuff. "I'm thinking you liked it too?" he covered his face. "Now now." he rubbed the other's back with a smile. "Let's get cleaned up okay?" the younger boy nodded.
As the water filled in the bathtub, Regulus whispered a quiet "Thank you." His older brother smiled. "Of course. What are brothers for?"