Of course Jim wanted to shrink himself even more. It was incredible being the size he was, and he wanted more of it. Or less of it, as the case may be. He blew up the balloon again, and softly said, "shrink me down to an eighth of an inch." His heart started pumping as soon as he said it, and it didn't stop as he let the air out of the balloon. He saw the waist of Judy's skirt rise up above him. She was a mountain now. He turned around and saw his bed behind him, now a vast plain. This was amazing.
Now it was time for action. Jim walked up to Judy's skirt and realized he was now so small that he could easily grab onto the individual strands of fabric. He climbed up her skirt without difficulty, and even had a chance to rest at the top of it. Judy's white shirt was tucked into her skirt, so he slid back down the other side of the skirt until he reached her shirt. The same principle held, and he started climbing up the fibers of her shirt.
This was too cool. At one point Jim turned around to look behind him, but he was already so far up that he almost made himself fall from the disorientation. He decided to focus, and soon he reached the bottom of Judy's long blonde hair, each strand now thick as a rope.
Jim couldn't believe he was grabbing onto his own sister's hair. He kept his feet pressed against her back and started climbing up, using her hair as a grip as if he was rappelling his way up a cliff. This was easier than he expected!
Of course, right then Judy decided to make her move. What was simply standing up to her was a titanic earthquake to Jim. He held on to her hair more out of instinct than anything else, and soon he was being flung about as his little sister walked around the house. Part of him was sure this was the end. Part of him couldn't believe his luck.