Lay a button-down shirt flat with the back of the shirt facing up. Slide your gift box inside the shirt.
Fold the top and bottom of the shirt over the gift. Use a safety pin to secure any excess fabric, if necessary.
Cross the sleeves so they wrap around the back of the box, then flip the gift right side up.
Tie the sleeves into a square knot. If your gift is narrow, you may be able to tie the sleeves into a bow.