The summer had peaked on that particular day. It was hot, there was not a single cloud in the sky and it was the longest day of the year. I had the pool to myself, and I was making the most of it trying to keep cool. Grandma came out of the back door with two glasses of orange juice on a tray. She placed the tray on the small wooden table between the deck chairs we had at the poolside.
"Mind if your old Grandma joins you for a swim?" she asked when the tray was out of her hands.
"Sure," I replied. After all it was her pool.
"Help me in then lad," she said as she walked towards the poolside. "I can't be bothered to walk round the other side to the steps."
I swam to the edge to offer a hand. Grandma was 58, but looked damn good in he one piece suit. It wasn't an old fashioned type of swimsuit that you expect old folks to wear, but it did make me wonder what she would look like in a bikini. I suddenly realised what I'd been thinking. I dunked my head under the surface of the pool to clear my thoughts. Grandma was now sitting on the edge of the pool with her legs hanging over the side and her feet in the water. As I came up for air my head was just at the height where the first thing I saw, as water dripped from my eyes, was Grandma's legs slightly apart and her swimsuit outlining her lips. I was immediately hard. I took my eyes away, but they just fixed themselves on the plunging cleavage the swimsuit had created.
"You going to come and give me a hand then Jack?" asked Grandma.
I didn't know what to do. My own Grandma had given me a painfully hard erection and I couldn't just swim away. As slowly as I possibly could I made my way to where Grandma was sitting. The pool wasn't too deep at that point, but I had to stay crouched down to disguise my throbbing member. Grandma leant forward and put her hands on my shoulders.
"Help me down then Jack," She ordered. I put my arms around her waist and lifted her into the pool. As Grandma lowered into the pool I felt her brushing against my bulging trunks. "Oh my," she said when her feet touched the bottom, "who have you been thinking about?" What could I say? I could hardly tell her that her own Grandmadson had got a huge boner over his Grandma.