Baby T is going to be a garbage man, so Little M is going to be a trash bag. This is how I made Little M's garbage bag costume.
I used white ripstop nylon (the same stuff windbreakers are made of) and didn't really worry about turning in rough edges, but you could really use any type of fabric, including fleece and felt.
1. Using a onesie that fits Little M, I traced out a wide oval, matching the top and bottom of the oval with the top and bottom of the onesie. (I should have made it 3-4 inches longer than the onesie though... you'll see why further down in the tutorial.) I marked where the hole for the neck should be and where the leg holes should be (I made them each about 2-3 inches wider than the existing leg and neck holes in the onesie, since my fabric isn't stretchy). You can also see that I changed my mind and decided to go even wider with the oval than I originally intended. The wider you go, the baggier the costume will be and the more you will be able to stuff it. I'm glad I went wider.
2. Cut out the oval. I traced it onto pattern paper (lightweight interfacing), then placed it on my fabric and cut out two ovals from the ripstop nylon. Mark on the fabric where the leg and neck holes will be.
3. Cut out elastic to sew onto the neck and leg holes. You'll need 6 pieces of elastic, because you'll sew it onto the front and back panels of the costume. Cut the neck elastic much wider than the neck of the costume. You don't want it to be tight and uncomfortable, especially on a young child. Each piece of elastic for the neck on this costume was about 8 inches long unstretched. For an adult, I would make each piece at least 16 inches long unstretched. Test it out by wrapping the elastic around the neck or legs of the person wearing the costume. Wrap it loosely, cut the elastic to size, then cut it in half to sew onto the front and back panels of the costume.If you gave yourself enough room when marking your leg and neck holes, the unstretched elastic should run about the length of the marked holes.
4. You will sew the elastic on the wrong side of the fabric. I sewed it right next to the edge of the fabric on the leg holes, but I wanted extra fabric to ruffle around Little M's face on the neck hole, so I sewed the elastic about an inch away from the edge on the neck hole.
To sew the elastic on, anchor it to one end of the marked leg or arm hole using a zigzag stitch. Go forward and backward for a few stitches to secure it. Then sew down the length of the elastic, still using a zigzag stitch, while pulling tight on the elastic. (I have to pull on the part of the fabric/elastic that has already gone under the sewing machine needle while pulling tight on the elastic in front.) This will create a gather when you're done sewing.
5. This is what the gathered edge will look like on the right side.
6. After sewing the elastic on the neck and leg holes of both pieces of fabric, lay the fabric on a table with right sides facing each other. Match up the leg and neck holes. Lay the onesie down and mark roughly where the arm holes should be. (You don't really even need the onesie for this: just give yourselves a few inches for the shoulders, then begin to mark your arm hole. To give yourself plenty of movement on non-stretchy fabric, bring the armhole down almost halfway down the edge.
7. Sew the two panels together. Don't sew across the armholes, neck hole, or leg holes. The areas where you'll sew are marked below in blue. You'll sew the shoulders, between the bottom of the arm hole and the outside of the leg hole, and in the crotch.
8. After trying the trash bag costume on Little M, I realized it needed to be a little longer. It pulled on the neck a little. So I added a little crotch extension, which was just a rectangle. I tore out the seam in the crotch, and then sewed in the extension, making sure to keep right sides together so the seams ended up on the inside. (At this point, I was a little embarrassed, because I had friends coming over, and I didn't want them to think this was a giant pair of granny panties on my kitchen counter).
9. I wanted my trash bag to have the red "drawstring" at the top, so I cut the hem off some velour pants and sewed it on in the same way I sewed on the elastic (anchoring it, then pulling on the red fabric as I zigzag stitched it.) I originally thought I'd use ribbon, but then I realized that if this was going around Little M's neck, I wanted it to be stretchy.
10. Once I had the costume sewn up, I realized I didn't plan a space to actually get Little M into it. Luckily, I made the neck hole wide enough that his whole body fit through it. If you made this for an adult, you would have to make sure that the neck hole, when stretched, would fit around the adult's hips. Another option would be to leave the seam on one shoulder undone and add velcro or snaps there. Add stuffing through the neck or arm holes (I am going to use newspaper, but shoved a cloth diaper in here for effect). You can also add elastic to the arm holes, but I kind of like them loose. I might change my mind in the next two days, though... we'll see.
And here is Little M, the cutest trash bag on the planet!