They do. Grace demonstrates some skills.

Sally cast another confused and disappointed look at her sister, then sat on the edge of the bed, covering her breasts with her arms. Grace looked at Mr. Carter, biting her lip, then glanced at her sister and ducked her head, blushing in embarrassment before slowly sinking to her knees.

"You'll keep Sally out of it?" she murmured as she reached out and started to unbuckle his belt.

"Just do your job," he growled softly. "Do it well and everything will be cool."

Grace pressed her lips between her teeth, worry evident in her face as she unzipped his pants, then reached in to squeeze his cock through his boxers.

"I'll be good," she whispered nervously. "I'll be very good."

Mr. Carter looked down at her as she slowly pulled his cock free, staring up past it's stiffening length at his hungry face. She took his shaft in her slim fingers, holding it as she lapped gently at the bulbous head. She kissed it, then rubbed it against her cheeks, all the while staring up at him with what she hoped looked like wanton submission.

His cock swelled as she played, and she felt wet warmth growing in her pussy. When she sucked the tip of his cock into her mouth and swirled her hot tongue around the sensitive flesh he moaned and shuddered with pleasure. He grabbed a handful of her hair, holding her in place as he started to rock his hips, slowly pumping his cock a little deeper.

Sally was grimacing in disgust, obviously repelled at her sister's behaviour but unable to turn away from the sight. Grace drooled on his cock, using her saliva as lube for her stroking hand. Her other hand clutched at his thigh as she slowly bobbed her head, taking him deeper with each movement.

"You're a good little cocksucker Grace," he groaned. "You've had lots of practice, haven't you?"

"Mmmhmmm," she murmured agreement around his meat, pressing herself deeper onto his swollen shaft. Her spit lubed hand slid down his cock to fondle his balls for a moment then slid back up as she pulled her mouth back, her fingers teasing over the sensitive head before she lowered her head down on him again.

She felt a flush of pride at his praise, knowing that she wasn't as experienced as he thought. She'd blown a few boys, but they'd all exploded pretty quickly, and she really hadn't had time to do as much teasing as she was doing. Most of her technique she's learned from porn, and she felt a surge of power at the pleasure she was giving him.

She bobbed her head quickly, slurping and gobbling as she devoured him, her eyes looking up as she strove to bring him off. She could feel his cock throbbing and pulsing, and knew his climax was near, that he was nearing the point of no return.

His cock was throbbing with the sweet suction of Grace's soft mouth, his balls tightening. He moaned as she bobbed her head faster, urging him to come as she purred and hummed around his turgid meat.

"Oh Fuck!" he groaned as his cock started to spasm. "Oh Yesssss!"

He held Grace's head tight, forcing her deep onto his cock as it spurted hot seed into her desperately sucking mouth. It felt like gallons were jetting out of him and she started to gag from his cock and the scalding cream that filled her. He pulled back, letting the last few ropes of semen splatter across her face. She looked up, her mouth open and full of come, her face spattered and submissive and utterly sexy, a fierce warmth building in her cunt.

"Eeeeeeew! That is so gross!" Sally squeaked, an expression of total disgust on her face.