Any discreet alternative to a pendulum for yes-or-no questions?

A small two-sided coin or token is simple and easy to keep in a pocket. Decide in advance which side means yes and which means no, then use it privately when you want a prompt.

You could make a tiny set of cards with yes and no written on them, shuffle, and draw one. It feels more like an ordinary card habit, though I’d treat the result as a reflection tool rather than a reliable way to settle important decisions.

If you want something that looks like nothing at all, use a random choice on your phone or pick an odd-or-even number in your head. Set the rules before asking, so you’re not changing the meaning to get the answer you hoped for.