Slipping is the term river fishermen use to describe the slow, careful process of using river current to move a boat slowly downstream, carefully controlling boat speed and direction, especially while searching for river walleyes. Simultaneously, as you control the motion of the boat, the moving boat controls the motion of your line and lure. One follows the other, orchestrated by how efficiently you master the process.
Point your outboard or electric motor directly into the current and exert just enough throttle to hold the boat in place. Now drop your jig or other lure to the bottom, and let out enough line to make contact when you lift-drop the lure. Once you determine the proper combination, back off lightly on the throttle. The boat will begin to drift slowly downstream. The more you reduce throttle, the faster the boat and lure move.
Assuming you've selected the proper jig weight for the current conditions -- probably 1/4- or 3/8-ounce -- the jig should move slightly ahead of the boat. Tap it along ahead of you, feeling for changes in bottom and for biting fish before the boat ever reaches them. This is a perfect combination for moving slowly downstream in modest current. In faster current, more throttle, a heavier jig, and a longer line are needed.
Use a subtle turn of your motor to change the direction of your downstream movement, from a drift to a directional maneuver. Steer the boat toward a visible edge until the lure and line intersect the change. Immediately turn your motor back slightly in the opposite direction to stop boat movement to the side. Now slowly drift your jig downstream, right along the current edge, making slight adjustments in direction to follow the surface edge.