Trout tickling is the art of rubbing the underbelly of a trout using fingers.1
If done properly, the trout will go into a trance-like state after a minute or so, and can then easily be thrown onto the nearest bit of dry land.2
The technique was a common practice used by boys, poachers and working men in times of economic stress, particularly during the 1930s depression-era.34
Poachers using the method required no nets, rods or lines or any other incriminating equipment if apprehended by the police or gamekeepers.
"Trout tickling" The fish are watched working their way up the shallows and rapids. When they come to the shelter of a ledge or a rock it is their nature to slide under it and rest. The poacher sees the edge of a fin or the moving tail, or maybe he sees neither; instinct, however, tells him a fish ought to be there, so he takes the water very slowly and carefully and stands up near the spot. He then kneels on one knee and passes his hand, turned with fingers up, deftly under the rock until it comes in contact with the fish's tail. Then he begins tickling with his forefinger, gradually running his hand along the fish's belly further and further toward the head until it is under the gills. Then comes a quick grasp, a struggle, and the prize is wrenched out of his natural element, stunned with a blow on the head, and landed in the pocket of the poacher.