Fire meditation.

This is what usually happens: Your volunteer sits and waits, for a long time, while you strain for a glimpse of their aura.

You are trying to relax and concentrate and master a tricky visual technique, all at the same time.

You subconsciously worry about what they are thinking of you.

Are they getting bored or impatient? Do they think you foolish, a failure, or both? This kind of pressure causes tension that effectively negates the relaxed state needed to see the aura.

Trying to get results under this kind of pressure, as a beginner, is next to impossible.