The fly stitch is worked vertically from top to bottom forming a Y shape.
Bring the needle out from 1 and put it in through 2. Then, bring it out through 3, which lies between and below 1 and 2. Pull the needle out from over the working thread to create a ‘V’ shape. To keep this V, put in the needle a little space right below in 4. Start the same process again a little bit lower and vertically, bringing the needle out in 5, putting it through in 6 and coming out in 7 ( which is the same as 4).