We were gonna catch a Tuk Tuk from outside the Grand palace some years back, and the Tuk Tuk driver was making absolutely no sense. I caught the guard out of the corner of my eye, and he raised his finger off the trigger guard in a "no" fashion, and had a small temporary smile. (You know the guards that stare into space for hours on end).
We excused ourselves from the Tuk Tuk driver, and I mouthed a quick "Khap pomm" in the soldiers direction. He nodded just slightly, and we were on our merry way.