I'm feeling like giving away some ideas!
Sometimes I do this at the end of a psychokinetic touche, lift effects. It works pretty much with double entendre.
You take two spectators and you ask them to place their palms towards the audience, the two spectators are in a line on stage, facing the audience, right palm toward the audience.
You ask one of the spectator to close their eyes, you come facing the one that has his eyes still open, and with your fingers you draw a triangle and a circle in his palm, make sure the audience see's it it is really important, you can even do mimics do show that you are drawing a triangle and a circle.
You ask the spectator with eyes closed to imagine something drawing in his hand, that he SHOULD feel something (the world should creates confusion).
Tell him that he will see two simple shapes, tell him that he might feel it or he might see it (this again creates confusion).
Draw it once more in the other spectator palm then ask him:
Now tell us what two shape you felt, (felt implies he feeled it or seen it) and voila.
It's better understood by your spectators if you did psychokinetic touches effects before, or else your spectators won't believe he genuinely ''felt'' the fingers drawing in his palm.