Tea has an important role in meditation. The main obstacle one faces while trying to stop and meditate is sleep, as soon as you become still and cosy, sleep grabs you immediately. The reason is that the mind is ever agitated and if the body is not equally agitated and has tired and slowed down then the thoughts do not follow the body and slow down at the same rate. They convert into dreams making the body sleep. So meditation is best done when you are well rested, that way the thoughts have already slowed down allowing you to remain awake. On top if you have a cup of green tea, it would be the perfect set up to practice meditation.
Buddhism in Tibet and China were spread by Indian masters: Padmasambhava and Bodhidharma being the prominent ones. Padmasambhava was responsible for the more popular tantric tradition and having a pandit background probably from Kashmir region, he introduced the Hindu concept of deities in Mahayana Buddhism. Bodhidharma was the one to foster the meditation tradition in Tibetan Buddhism. One of the legend of the origin of tea says that once Bodhidharma was practicing meditation but was falling asleep again and again, so he got a bit irritated, pulled his eye lids and threw them out of the window, which grew later as tea plants. Now if you remember Bodhidharma as you sip green tea you may be able to remain more awake and meditate better.