I don't do a lot of reality checks during the day, but I am very consistent in performing them whenever something strange/unusual/unexpected happens, as well as whenever I see a dream sign.

One situation that I haven't been able to cover is this:

In dreams, my singing voice and technique is dramatically improved.

In waking life I sing in a choir, and as a soloist in front of the choir. I would like to be able to do a reality check whenever something causes me to hit the "sweet spot" where my tone is suddenly better than expected. Or if I'm suddenly able to hit a difficult note with less effort than I'm used to.

I sing either facing the choir or an audience, so everyone is looking directly at me. How do I RC without anyone noticing? It has to be something that can't be seen, and also something that doesn't require an awful lot of thought, because the really good stuff tends to happen during improvisation, which requires a lot of focus.

Any ideas?