To walk or tramp about; to gad, wander. < Old French – trapasser (to trespass).

Travelers in desert lands who face prolonged thirst have learned that a small pebble placed on the tongue draws saliva into the mouth and relieves the unpleasant feel of a parched mouth, allowing the will to fasten again on the oasis objective.

Pebble on the Tongue: Fork in a Brazilian Street