I was going down to my pool for a fun time. Sure, I could use a Beachball potion and turn into an actual beach ball. But what I had planned was a lot more fun!
I had brought with me a 50% shrink potion and a 3-hour potion extender. I got out the air pump and 3 large beachballs. After pumping up the beach balls. I drank the potions, with the air pump in hand so it would shrink with me. I felt the strange sensation of becoming smaller, until I was half my original height.

I was now close to the same height as the 4-foot beach balls. I rolled them over to the edge of the pool. I sat down in between them. I put the hose into my mouth and turned the air pump on myself. My body began to inflate as air forced its way into me as I began to pump myself up. I managed to focus the air mainly into my chest, keeping my limbs mostly uninflated. My chest swelling rounder with every pump. Soon my body was perfectly round like the beachballs around me, but with short limbs and a tail. But my body was still smaller than the beachballs. So I continued to pump and pump and pump. My spherical body becoming bigger and bigger.

Finally, after much pumping, I was slightly bigger than the beachballs. I spit the hose out and let go of the pump. It fell to the ground with a clang. I sat there for a while admiring my ballooned body. I was now just as full of air as the balls around me. After sitting in the sun for a bit I decided to finally get into the pool. With some effort I managed to stand up with my short, slightly inflated legs protruding from my spherical form. My arms now shorter than the circumference of my body. So I had to belly bump the balls into the pool. One after another the fell into the pool with a plop. Then it was my turn. I turned around, so I would land on my back, and bounced as much as my short legs could manage into the water. I landed with the same quiet splash as the beachballs. I could deflate at any time but would remain shrunken for a few hours. So I relaxed myself and gently floated around the pool, for now I was just another beachball in the pool.