Jon was just about to step into the shower when his mom made her wish, and suddenly he was no longer naked. But he wasn't wearing his usual clothes. Instead, he was wearing a skirt suit, kind of like the ones that his mom wore to work.
Thinking that this definitely had something to do with the stone, he ran back to his bedroom to see who was using it. But when he got there, he saw that the stone was still sitting right where he left it. It hadn't been moved at all.
He picked it up and looked at it, wondering if maybe it was broken or something. What happened to him was definitely not normal, so it must have been caused by the stone.
To test the stone out (to make sure it was still working right), Jon said "I wish ..."