The steps to sew without leaking velvet are as follows:

1. Choose a suitable position for sewing. You can choose to sew embroidery patterns around or near the holes, which can effectively cover the holes and increase the beauty.

2. When sewing, choose strong embroidery thread to ensure that the patch is firmly fixed on the down jacket.

3. When sewing, try to keep the stitches neat and detailed to avoid affecting the overall beauty.

4. After sewing is completed, use small scissors to cut off excess thread to ensure that there are no protruding threads around the patch.

5. Use an iron to iron the sewn part flat, so that the patch can be better combined with the down jacket and avoid wrinkles.