Press coils of clay into the "slipped" channel. This will reinforce the joint, making it less likely to crack during drying and firing.

Use the handle of tool #8 or a round sided pencil to roll over the clay coil on the seam line. This packs the clay down and flattens it.

Use the fettling knife to further smooth and flatten the joint.

Use the frosting knife (tool #10) to paddle the seam line.