She rested for a few moments until she removed her arms from around his head. He took a break from kissing her and she uttered.
"It feels amazing. I am sorry for coming without you, Ben. Let me be on top this time. You just relax and I will make you feel good."
They reversed their position by rolling over, him lying on his back and her riding him in a cowgirl position, his penis never leaving her comfortable insides. As soon as they were in position, she started moving her hips up and down awkwardly, since she wasn't used to the position, her ass cheeks clapping against his thighs and her large tits bouncing in rhythm. It was a great sight and Benjamin took hold of her boobs, massaging them and teasing her nipples. Feeling that she was in control for the first time during her first sexual experience excited Grace, enhancing the feeling of his cock hitting strongly against her womb as well as his hands on her breasts. She began going faster and faster as she got used to the position, expressing her euphory in a loud voice.
"It's so good, your dick feels so good, Ben! Are you feeling good too? Do you like my pussy?"
"Yes, it's incredible, Grace. You are so hot and tight."
He was still careful not to speak too loudly, just in case he was heard, while her shouts could be taken as fantasy talks during a masturbation session and didn't matter. His words only made her hornier and she accelerated the pace of her waist movements, impaling her cunt on his dick. The exceeding stimulation soon made her do one big hips movement, almost removing his member from inside her, only to violently drop down on him, his glans poking strongly against her cervix. This pushed her to yet another orgasm, squirming on top of him and sending her juices on his groin.
She trembled for some time, enjoying her climax, and soon resumed her movements, seeking more pleasure. She bounced on him a few times before feeling that something was missing and bent her upper body, seeking yet another kiss. Benjamin easily satisfied her wish, removing his hands from her tits and using them to hold her head, starting a deep tongue kiss once again. She resumed moving her waist, in an exact inversion of the start of their mating session. They enjoyed the double stimulation, entangling their tongues while Grace was fucking herself on him. She kept at it for a few minutes, the pleasure slowly rising, until both of them couldn't hold it anymore. They climaxed at the same time, Benjamin groaning his pleasure during their kiss and her moaning her joy in his mouth. He sent several strong jets of sperm inside her, filling her even more, and she appreciated the feeling, her twitching flesh contracting strongly each time she felt the semen invading her.
She started to tear up after so much pleasure and her climaxing and perverted face switched a gear in Benjamin's mind. Without waiting for their combined orgasm to end, he started pumping into her from the bottom, sending powerful cock strokes in her twat. Surprised by the sudden change, she separated from his lips, stopping their kiss and moaning loudly.
"Ah! Ah! Ah! Ah!"
Her moans excited him even more and he went even stronger on her, using all the strength of his waist to reach as deeply and as powerfully as possible inside her. The strong stimulation forced her to let her head fall next to his, without the force or the will to support it, just focusing on the incredible pleasure. Soon enough, she had another orgasm, which didn't stop Benjamin at all, on the contrary. He rolled over again with her and switched position once more before turning her on her belly and rising her ass, sending his cock all the way inside in one big thrust. He continued to bang her like that, bestowing her with more and more climaxes. She had completely lost any resistance by that point, simply letting him do anything he wanted with her, her talk about pleasuring him long forgotten.
With her ass in front of him and remembering the way she had been masturbating, an idea popped into Benjamin's mind. He put one of his fingers in his mouth to lubricate it and sent it inside her ass, penetrating her puckered hole in one go. There was little resistance, as if to prove that she was often playing with it, and he inserted it all the way to the knuckle in one try.
Feeling the sudden attack on her ass, she squealed sonorously.
"Aahh! My ass! Yeess! Finger my ass, I love it! Use more fingers!"
It was always nice that women expressed their desires so easily. He quickly obeyed her, lubricating another finger and sending both of them once again in her ass, making her shiver in pleasure. Seeing his sister feeling it so hard turned him on to the max and he launched himself in an extreme pistoning of her cunt, the sound of his waist slamming on her ass cheeks resonating in the room, all the while fingering her ass as hard as he could. She was sent in a flurry of orgasms, not getting any time in between them, howling her ecstasy.
"Cumming! Cummiiinng! Aaaaahhhhh! Again! So strong! So gooooood! Fuck my pussy, fuck my pussy, fuck my pussyyyy!"
Happy to oblige, he furiously pumped her snatch at full power without a stop for several minutes. Finally, when he felt her constantly clutching cunt relaxing itself and her strength leaving her body, he went into a final spurt until he let himself go one last time, sending his sperm deep inside, groaning his pleasure in a low voice. He waited until his ejaculation was finished and removed his penis from her pussy, checking his sister's condition. She had her head on her pillow and was unmoving. He turned her on her back, only to see that she had fainted from too much pleasure, her face full of tears and drool. Her cunt was still opened in the shape of his dick and his semen was slowly flowing out from her hole, dripping on the sheets.
He positioned her in a way where she would be comfortable enough, turning her a little toward him, and snuggled inside her large bosom, cuddling with her until she woke up.