You know those great little snaps at the bottom of a onesie that makes it so easy for getting to diapers for changing?! Well they are also great for keeping those adorable button-ups tucked into those tiny slacks, while still having the convenience of a onesie. And all it takes is a little cutting and a couple straight stitches.
My kids also have a great knack for destroying beautiful white onesies, so I do don't feel so bad cutting one of them up for things like this. Of course you could always use a non-destroyed one if you prefer.
First you want to cut off the bottom of the onesies, giving yourself at least half and inch seam allowance and making sure it will be long enough to fit your babies torso. Turn right sides together, line up the seams on each side and pin, then stretch and pin the front and back, then pin in between those gaps. It should look like picture #1.
With the onsie section on top, start on one of the side seams and sew a straight line giving that half inch seam allowance (or more depending on how tall your bottom seam is, you want to make sure to sew above that hem). Don't forget to back stitch. As you sew, the top will have to stretch a bit to stay lined up with the non stretchy fabric.
Turn inside out and press the seam down towards the onesie section. Starting on one of the side seams, sew as close to the edge of the button up as you can, sealing in that seam to keep it nice and flat against the body. Since the button up already has a finished edge, we don't have to worry about the raw onesie edge fraying.
Voila! We are done, and we know that handsome little man will stay sharp looking all day with his perfectly tucked in little shirt. I didn't take an after picture, I just didn't think it was necessary. If you have any questions, then just let me know.
-Pretties and Pastries