Sam and Dean were in the Impala outside of Madison's apartment. The night before Sm had stayed with her while Dean hunted the werewolf. Sam was too shy to make a move on Madison, but he had been thinking about it all night. It would have been so easy to grab her and kiss her, he wanted to so badly, but he had missed his chance.
There was a knock on the window, jarring Sam from his thoughts. It was Madison. Se asked what they were doing in front of her apartment building. They explained that it was a precautionary measure. Madison invited them both in, to Sam's dismay. He wanted to spend time with her alone, and do the things he had been thinking about for the last eight hours.
They followed Madison back to her apartment, Madison shocked them both by locking the door behind them. The boys were prepared in case she was going to turn, Dean had his hand on the gun. Then Madison did something even more unexpected. She told Sam to take off his clothes. He looked nervously at his brother, "does this count as incest?" He asked himself. He undid his belt and pulled down his pants.
Madison and Dean gasped in unison, when they saw how big his cock was. Sam tried to reach for his member, but Madison grabbed his hand, he had no control. She grabbed a scarf from the closet and tied his hands behind his back. When he was situated she moved over to Dean.
She started massaging her breasts, moaning quietly. Then she went south, she thrusted two fingers into her dripping pussy. She used her other hand to massage her clit. Both of the boys were driven wild by that point. She wanted to push same even farther over the edge. She stood up and grabbed him by the shirt, bringing him over to the couch. She pushed him on the floor and sat on the couch. She forcefully pushed his mouth against her warm pussy. He licked and sucked and nipped until she was screaming with pleasure.
Dean, watching this was stroking himself. Sam moved so he could have his turn, he slowly put his dick inside of her. She whimpered from the size. While Dean controlled her pussy, Sam wanted her mouth. He started thrusting his cock in her mouth, and didn't stop until she was shaking.
They continued to have even hotter sex until the morning, until they fell asleep, Dean's cock still inside of her.