If you want to convince your friends that you might be gone for a while, here are some things to consider, but make sure that this joke doesn't hurt your friendship: 1. **Work reasons**: You can say that you've been given a very important project and you have to devote yourself to it, so you may not be able to contact them for a while. 2. **Family matters**: Mention that there is a family matter that needs to be dealt with, such as a sick relative or something that needs to be taken care of, so that your friends will understand that you are temporarily unavailable. 3. **Self-cultivation**: You can say that you feel a little tired and want to use some time for self-reflection or recuperation, and hope to temporarily reduce social activities. 4. **Travel plans**: Pretend that you have been planning a trip for a long time, and you may go to a place with no signal and you can't contact them for a while. 5. **Mysterious adventure**: You can make up a story, such as you are going to participate in a mysterious activity or experience, which will make you temporarily unavailable. No matter which rhetoric you choose, it is recommended to reveal the truth in a humorous way at the end to avoid making your friends too worried.