Fuck her

You pressed against her, and your sister's pussy opened to accept your big black cock. She let out a muffled moan as you stretched her out. She was tight, but not so tight that you were hurting her. She started to orgasm almost at once and you knew there was no going back now.

"Oh fuck," she moaned.

You stood for a moment, balls deep in your twin sister, feeling her pussy spasming around you. Fuck she felt good. You'd been with girls who had tight pussies and you'd always worried you would hurt them. You'd been with girls who had loose pussies and it was never as good. Marcie was almost perfect.

"You like that?" Dr. Grant asked.

You glance at the doctor to find that he has his own big cock out and he is stroking it as he watches you fuck your twin.

"We don't...have...all day," he said. "I need...cream pie...for an Alpha status."

With that, you pull back and then thrust back into her, causing her to cum harder. She moans into the exam table as you start pounding in and out of her. After less than two minutes, Marcie had cum so much she already had her own juices running down her thighs.

Off to the side the pervy doctor is now breathing hard as he frantically jerks himself.

All these year's you had been careful fucking various girls, either using a condom or pulling out. Now you were about to take that chance and give a bareback creampie to...your twin sister? The thought should have been disgusting, but it actually made things hotter.

"I'm...almost there...you'd better be...too," the doctor moaned. "More patients...to sort."

Fuck, you didn't want to go through this only to not get your sister an Alpha pendant because you just took to long. You reached down and spread her cheeks, giving yourself a good view of her asshole. It was nice. You couldn't even imagine that your prim and proper sister had done anal before you, but you could easily see why a guy would want to get in that ass.

"Fuckin' give me your nut, Derek," Marcie moaned. "I need it...bad. Fill me up."

Still staring at her asshole, you finally climaxed. You thrust harder, shooting your seed into your twin sister's fertile young womb. At the same moment, Dr. Grant grunted and started shooting his own massive load into the floor.

You you were spent, you stepped back, your legs feeling weak. Marcie crawled onto the exam table and curled into a ball as she continued to cum. Dr. Grant just casually shoved his cock back into his pants.

"That was the hottest sex I have ever seen," he said as he reached into a nearby cabinet and grabbed two sorting necklaces. He handed them both to you. "You both deserve these. Enjoy life at the top."

With that he strode out of the room.