On The Spot Meaning

(idiomatic) In a particular place.

Example:   He liked the house, so he made an offer on the spot.
  All the sudden questions put him on the spot and he had to think quickly.
  This report comes from our man on the spot in Gaza.
  We exercised by jumping up and down on the spot.
1928, Dorothy L. Sayers, "The Abominable History of the Man with Copper Fingers", in Lord Peter Views the Body,
  I had accepted an engagement to go out with Mystofilms Ltd. in Fake of Dead Man's Bush—the dwarf-men picture, you know, taken on the spot among the Australian bushmen.