He catches you watching.

"You hear that kiddo?" he said loudly, turning to the door. Your heart froze in your chest as his eyes locked onto yours. You felt like a child caught sneaking cookies, horrified that you were caught. None of this had gone how you expected when first telling Carrie to mess around with your grandfather, you never had any intention of him finding out you wanted this in any way. Now you felt embarrassed at how he had caught you watching and anxious for what was to come.

"Babe?" Carrie said as she jumped to her feet. You turned your attention to her and she had a massive grin on her face. She was loving this.

"C'mon in, get a better look," your grandfather said. After a few seconds you pushed the door open slowly, standing in the doorway with a clear tent in your pants and your face red with embarrassment.

"Never knew you were such a freaky little cuck. I planned to just take her slowly behind your back while I was here, but this makes it way easier," he said. He reached over to Carrie, hand moving to her ass as he pulled her tight against his wrinkled body.

"Go get a tape measure, your bitch here is gonna measure us both to see just how much bigger I am so we can settle this little bet," he said. He immediately turned to Carrie and planted his lips on her, making out with your girlfriend right in front of you as you processed his command. It took a few seconds for you to tear your eyes from what was happening as your grandfather's hands slid around Carrie's naked body, but soon you found yourself walking away. It was like your body was on autopilot as you left to go find a tape measure.

It took a minute of digging around before you got one, and as soon as it was in hand you practically sprinted back to the bathroom. As you walked back in, Carrie was kneeling on the bathroom rug and your girlfriend's lips were wrapped around the head of your grandfather's cock. Drool and precum were dripping down onto her tits as she bobbed back and forth. Your grandfather smirked as you walked in, giving Carrie a tap on the side of her head.

"You can stop for now cock slut," he said, and there was a slight pop sound as Carrie slid back and stopped sucking his oversized dick. She licked her lips after, a look of pure delight on her face that you'd never seen before. You held out the tape measure and Carrie smiled up at you as she grabbed it, her attention immediately returning to your grandfather.

"Get over here and pull out your little thing already, we all know you're fuckin hard," he said. Carrie sat back and stretched out the tape measure as you stepped beside your grandfather, dropping your pants and underwear to the floor before kicking them aside. Your cock jutted out, hard as can be with a bit of precum at the tip from how turned on you'd been. You looked down at yours, then over to your grandfather's.

Standing next to him made the size difference even more obvious. It was already clear that he was bigger, but as you stood beside him it was an even more clear difference. His cock was noticeably thicker and stood out quite a bit more, and you'd swear you saw him still getting bigger and hard as Carrie eagerly moved forward. She slid close to both of you and stretched out the tape measure against yours.

"Just a bit over six inches long," she said, a look of clear disappointment on her face.

"You always said you were seven ya know," she added, with your grandfather scoffing.

"Now I get to measure the real man," Carrie said. She stretched the tape measure against your grandfather and you saw his cock throb at her touch.

"You're...you're just over two and a half inches longer than him," Carrie said. Her voice was soft and almost...joyful. Excited. She smiled up at the both of you.

"Almost nine fucking inches of perfect dick," Carrie said, running her fingers along the length of it as she turned to you.

"God he makes you seem so small," Carrie gleefully said, with your grandfather laughing a bit. You had lost by a massive amount, much to the delight of your girlfriend, and now this little bet meant that your grandfather had two commands to give Carrie that she would obey without hesitation. You were left standing there, embarrassed and aroused and worried at what he would want first.

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