To change the Tab position, access your ContactUs.com admin panel. Go to Forms and Select the form. Then, on the left panel, go to Form Triggers.
Here you will select "Tab Settings", and you'll be able to change the Tab Position. You can also change the Tooltip settings, such as headline and body. Once you've selected the desired position, make sure to save and publish the changes. Refresh your browser's cookies and cache to see the changes live.