When setting up your tilt, choose the option to make it 'private'. This means that your followers won't be notified, and the tilt page won't be searchable in Google. It also won't be visible to other users who view your Tilt profile or appear in the world feed.
Only people who have the specific link to the tilt page will be able to view it and chip in.
Here's how the option appears on the web:
If you're using the mobile app, select the 'private' toggle: