The easiest way to tape your lithium batteries is to first lay a strip of packing tape on a flat surface, sticky side up. Place the batteries onto the sticky strip of tape. Finally, press another strip of packing tape (sticky side down) on top of the batteries, making a simple package that prevents the batteries from slipping and contacting each other.
You are trying to cover the parts of the battery that deliver power to the device they would be inside. These would be the "contact points."
Here's an example:
Why do I need to tape up batteries? This is a hassle.