My granddaughter liked spending time with us during the summer months when she was off school. Her parents often would be off somewhere overseas, traveling together, and seeing the world. Kate never wanted to go with them. She said it was boring and no fun. When she turned 18 and graduated high school, she said she wanted to spend one last summer with me and my wife before going off to college. That summer was a special one.

A few days into her time with us, I got up one evening to find quiet moans and murmurs coming from the bathroom. Knowing my wife was still asleep in the bed, I figured it must be coming from Katie and sure enough I was right. Peering into the bathroom, I saw her on the counter completely naked, her fingers playing with herself quite frantically.

I couldn't believe what I was seeing and though I know it was wrong, I couldn't turn away. It had been so long since I saw anything so young and perfect as she was. I watched as she made herself orgasm twice before finally turning around and smiling at me through the crack in the door.

"I know you're there Grandpa. Come in here before Grandma sees you." she said standing to face me, her full naked body on display. I took a breath and stepped inside, closing the door behind me. My eyes couldn't believe what I was seeing as hers looked me up and down. I suddenly became aware of the throbbing bulge in my pajama shorts as her eyes locked on it with a smile.

"Damn Grandpa. You're even bigger than mom said you were." she said as she took a step closer. So her mom told her about the things we did when she was her age? I thought that would have been kept between us but apparently not. Her mother used to crawl in bed with my wife and I, push herself between us, and grind against me during the night. A few times, she'd pull my cock out from my shorts and let it grind against her wet folds, even slipping inside for a pump or two. She hadn't talked about it since our last time when she was 24 so I had no clue it would ever be brought up to her daughter.

I smiled as my eyes looked at her body, firm perky breasts and neatly shaven pussy. She walked closer, her hands reaching out and pulling down my shorts. Her eyes widened as a smile crept across her face. I lost control and before I realized it, I spun her around, bent her over, and slid my cock inside her wet little kitty. It felt better than I could imagine as I started thrusting harder and faster inside her. Her moans quietly filling the bathroom. I hope my wife doesn't wake up.

We spent the next hour in the bathroom together moving all over as she moaned with each thrust. She seemed to become lost in pleasure as I filled her so full. She begged me to cum inside her but I told her her mother would kill me if I did (after all...how do you think Katie was conceived?), so at the last moment I pulled out, grabbed her head, and pushed my cock down her throat. Her eyes rolled back in her head as I throbbed and came, shooting my cum deep down her throat.

She smiled and looked up at me in a daze.

"Grandpa...I might be staying a bit longer than planned if that's okay with you?" she said with a smile.

"It certainly is sweetie."

"Grandpa's bonding time with his Granddaughter"