Tea can be found by the side of the Coffee in the Coffee Shop. You can drink the tea seven times before it disappears out of your inventory, or your hand. It is based on British tea, instead of the Jasmine, Oolong or Green tea which was added after it. You can purchase it for 2 Bucks, and it is the cheapest item available at the Coffee Shop.
The mug is a darker blue color with brown tea inside.