It was happening yet again. Sebastian was fucking Cecile. The three of them were spending the summer together and their sexual drives were very intense. He talked about it with his sister, and they concluded it would be better to continue to host Cecile in their home, where they would be able to keep track of her. Cecile would go back to England at the end of the summer anyway. Cecile spent every night in one of their beds and sometimes all three of them would spend the night together in the same bed. Sebastian's sessions with Kathryn went on as scheduled. That, along with fucking Cecile and the threesomes sent his sexual drive through the roof. He was constantly craving it, looking for any sign from either Cecile or his sister. There were many other girls he was interested in, yet with Kathryn and Cecile in the house with him, he didn't feel he had to bother. And the sex with Cecile was way different than a couple of years ago. She was more assertive and intense and he could never get enough of her.

They have been at it for a while and Sebastian was on top. They were so familiar with each other's body and moves and they were completely in sync. He loved the way her nipples felt against his nipples and they way she kissed him while he was thrusting. He was focusing his energy on trying to make it last as long as possible. Suddenly, Kathryn burst into the room.

"I need to talk to you!", she said.

"Little busy here, sis", Sebastian replied as he was panting.

"Hurry up!", Kathryn demanded and Cecile giggled.

"Oh what is it brother?", Kathryn said, "You don't wanna cum? You wanna make it last?"

"Fuck yeah", Sebastian replied.

"We'll see about that", Kathryn replied. She got down on her knees next to the bed and began to kiss his neck as he was fucking Cecile.

"Please, sis", he said.

"Oh but you fuck so awesome, brother, I love that ass so much", she said as she gently slapped his ass.

Sebastian was biting hard on his lower lip and took very deep breath, determined to keep going.

"Oh it's so cute how you're trying not to cum", Kathryn continued to tease him. She kissed his neck again and worked her wat down to his back. "Wow brother, your ass looks amazing when you're fucking!", she said and planted a kiss on his ass.

Sebastian could not hold it any longer and he uncontrollably released his load.

"Fuck sis!", he exclaimed as an orgasm flowed through his body.

Cecile was laughing.

"I told you", Kathryn said.

"I really thought you could do it, Sebastian, sorry", Cecile said.

"Huh? What's going on?", Sebastian asked.

"Oh you see brother," Kathryn said, "We had a little bet going on. I said I could make you cum in a second and Cecile was sure you would be able to hang on."

"Yeah I was really rooting for you", Cecile said giggling, "Wanted you to fuck me longer, oh well."

"So what was the bet?", Sebastian asked as he got up and looked for his cloths. "What did you win sis?"

"Oh this is just something between me and Cecile, brother, sorry, it's a secret. I'm gonna get some breakfast, you wanna join me?"

"Sure", Cecile said.

"I'll catch up with you later", Sebastian said.

Cecile got dressed and as she was about to leave his room she said: "Tell me when you wanna fuck again, OK?"

"Yeah OK", he replied.