quake in one's boots
to be afraid, to shake from fear
I was quaking in my boots when my boss told me to come to his office.
Balls are spotted by placing them on the long string as close as possible to the foot spot and between the foot spot and the foot rail, without moving any interfering ball. If the spotted ball cannot be placed on the foot spot, it should be placed in contact (if possible) with the corresponding interfering ball. However, when the cue ball is next to the spotted ball, the spotted ball should not be placed in contact with the cue ball; a small separation must be maintained. If all of the long string below the foot spot is blocked by other balls, the ball is spotted above the foot spot, and as close as possible to the foot spot.