On the garment, mark the placement of the slot. This will either be lengthways on the center back or parallel to the neckline. Ensure to check your placement is straight and level. If you are creating the adaptation for a harness, put the harness on your dog, then the garment to be altered and find the location of the harness toggle to better mark the garment.

Lay the SLOT BINDING RIGHT SIDES together with the garment. Pin and stitch as shown by the central rectangle on the pattern piece.

Using small sharp scissors, snip along the inside length of the rectangle, forking out into the corners (be carful not to snip through the stitches).

Turn the garment to the WRONG SIDE and pull the SLOT BINDING through the snipped area.

Flatten the seam by hand so the SLOT BINDING lays flat on the WRONG SIDE.

Top stitch around the newly formed slot, approximately 1cm away from the seam.
Trim the excess fabric of the SLOT BINDING if desired.