Try changing the point of view or the setting. It can breathe new life into your story. Or start writing a different scene and see if that unblocks your creativity for the stuck part.
Another option is to check if there is something caught in the zipper, like a thread or a small piece of fabric. If there is, carefully remove it with tweezers or a small pair of scissors. Be very careful not to damage the zipper or the item it is on. In anime cosplay items, for example, the fabric might be delicate, so extra caution is needed.
You could try rubbing a pencil lead on the zipper teeth. The graphite in the pencil lead can act as a lubricant. Just make sure not to get graphite all over the anime item if it's something that can be easily stained.
Take a break and clear your mind. Maybe go for a walk or do something unrelated to writing for a while. Sometimes, stepping away helps you come back with fresh ideas.
If you're stuck in 'My Time at Portia', first try to review your current quests. Maybe you missed an important item or conversation. Check your quest log carefully. For example, if it's a building quest, ensure you have all the required materials and the right blueprints. Sometimes, bugs can also cause you to be stuck. In that case, try restarting the game.
I'd say go back and review your outline or character development. Sometimes getting back to the basics helps. Also, try freewriting about your characters or the setting to get the creativity flowing again.
Well, in a fanfiction where my limousine is stuck in traffic, it could be an opportunity for some interesting character development. I might start a conversation with the driver, learn about his life story. Or I could look out of the window and observe the people on the street, getting inspiration for a new project or just daydreaming about a different world. It could also be a chance for a surprise encounter, like meeting an old friend who just happens to pass by.
One helpful exercise is to take a break and do something completely different, like going for a walk or listening to music. It can clear your mind and give you fresh ideas.