Apparently this is the method used in Theta Healing to reach the theta brainwave state quite quickly, claimed by the founder of Theta Healing to 'work every time with every person'.
From: http://www.answerswithin.net/theta-healing.htm
Here's how it works:
Close your eyes.
Imagine a ball of light or energy in your heart area.
Move this ball of energy up from your heart space, and out the top of your head.
Say the name of God, Source, Father/Mother God or whatever works for you. Now you are in Theta.
An alternative version I read about:
1. Close your eyes and concentrate on a point 3 feet above your head. You will soon be in alpha.
2. Continue to focus on that spot. Chant (mentally or out loud) "Mother, Father, God, Creator".
That's it! Voila, instant Theta!
If someone happens to have access to an EEG machine maybe they can try and verify if this really works.