It's too late for that

What little willpower he had was washed away by lust he had for his sister's milkers. With a sudden boost in strength and agility he'd never had before, he leapt forward, slamming his sister's back against the cooler.

"PARKER! NO! PLEASE DON'T... Oooohhhhhhh," she began to scream in terror, before moaning as Parker fondled her breasts. They had somehow even grown more sensitive, her nipples hardening in less than a second as waves of arousal flowed through her with each grope.

"N-no! S-stop... this... ooohhh.... p-please d- ooohhh.... gohhhddd.... stop th--oooooohhhhhh fuckkkk hmmmnnnggg..."

Rachel began drooling. The fear she had was still there... and yet... it was paired with some of the greatest pleasure of her life. It felt like both of her breasts were giant clits to be massaged.

"So hot... so hot... so hottt...." Parker repeated over and over, his thoughts rapidly becoming more simplistic and primal. He didn't even see his sister anymore. Just a piece of meat to impregnate and use. Without thinking, he ripped his pants off with another burst of strength beyond anything he'd ever been capable of. His dick had grown to be nearly a foot long, fully hard with pre-cum already building.

With a mighty jerk of his arms, he span Rachel around, so he could grope her from behind.

"Hmmm... no.... ahhh... AHHHH... stopppp.... Hnnnggggg... sooo goood... noooo," Rachel stammered. Without realizing it, she groped herself in time with her brother.

He squeezed on her breasts so hard that she shrieked in a mixture of pain and ecstasy, before using them as handles to throw her to the ground. As she fell, her knockers prevented her face from hitting the ground, as she laid on them like pillows.

Seeing her in this positioned caused Parker's dick to throb even harder, and he rapidly ripped off her skirt and panties.

Rachel tilted her head towards her assaulter. The part of her still capable of rational thought looked at him with pleading eyes, begging him not to do it. And yet, the other part of her wiggled her ass invitingly, begging him to go in as her pussy moistened.

Letting out a moan, he grabbed onto her ass for support, while putting the full weight of his body onto her back, pressing her into her gigantic boobs, causing her to moan again. That moan was then surpassed by her squeal as he **** his dick inside her.

With all his might, Parker thrust, smacking his balls against her ass and making them jiggle. In fact, with each thrust those same balls grew larger, as did his entire body. His muscles were swelling, his imperfections disappearing. And as he grew stronger, it only increased his virility, and he thrust harder, faster, smashing his sister with everything he had.

"PARKER! PARKER! THIS IS WRONG! Please! THIS IS.... SO... SO... Sooooo..... GOOOOODDDD!" She screamed, as her reservations were quickly being erased as the virus overwhelmed her. Her hair lengthened and skin blemishes disappeared, until it was practically shining.

Her increase in hotness only encouraging him more, Parker picked her up around the midriff and slammed her against the wall without taking his dick out of her or slowing down in his thrusts. He then adjusted his hands to her waist to support himself, while Rachel leaned her arms against the walls.

"You like that! You like that, you little slut!" Parker cried, unable to think about anything else.

For the briefest moment, Rachel wanted to deny it, but the ecstasy she felt snuffed it out by the primal joy of being rutted.

"Yes! Fuck me! Fuck your slutty sister! Fill me up! Breed me! Make me your baby factory!" Rachel cried back, surrendering to the virus as her eyes glazed over.

"I will, you little cum bucket! When I'm done fucking you, I'm going to fuck you again, and again! I'm going to fill you with so much spunk you'll be bursting every day!"

"Ohhh yes! Do it! Do it more! I'm just your property. Use me! USE ME!" Rachel screamed, as both siblings came close to cumming. Just a little bit more...

"WHAT THE FUCK IS HAPPENING?!" a voice cried.

The siblings looked over to see the girl from the gas station counter looking at them with wide eyes, and her mouth hanging open. She had missed what had been happening because she had been listening to music, but she had, for some reason, come to this area of the store to see this insane display.