How the test works
Pick two real options: option A and option B. Flip a coin and decide in advance which side means what. When the result appears, do not focus on obeying the coin. Focus on your immediate reaction.
Watch for relief or disappointment
If you feel relieved, the result probably matches your real preference. If you feel disappointed, that is a strong signal for the other option. The useful part is noticing the reaction before you explain it away.
When to use it
This works well for small decisions: where to eat, which task to start, how to spend a free hour, which gift to choose, or which version to test first. It is best when both options are reasonable and you are simply stuck.
When not to use it
Do not use a coin flip for major financial, medical, legal, or irreversible decisions. In those cases, your reaction can be a clue, but it is not enough on its own.