You will need:
One regular fit t-shirt that sits comfortably over your chest
Thread in a matching or contrasting colour
One safety pin
We begin by cutting off the sleeves,
then cutting a straight line just under the neck.
Hold the t-shirt up to you and decide where you want the bottom edge to sit. Mark that area with tailor's chalk, or a pin. Add two inches to the final length and trim the excess from the bottom. Do not discard this piece as we'll need it later on in the project.
We need to hem arm 'holes' to ensure they don't fray.
Next we're going to create a channel at the top for the first drawstring.
Fold the raw edges under by about one inch and pin into place. Sew along the line, keeping as close to the raw edge as possible to ensure that the channel is large enough. Repeat on the second raw edge and the top portion is complete.
Decide which side you would like the drawstring on the bottom to be, and make a cut in the the side seam about an inch and a half long.
Tuck the raw edge under and pin. Sew along the line, making sure to keep the channel wide enough to pass the drawstring through.
Here's where that discarded piece from the bottom of the t-shirt comes in. Cut off the hemmed edge and set aside (for another project, perhaps...) Take the remaining 'tube' and cut along one side seam to create one long piece. Now cut along the length to make it into two long pieces.
Now we are going to tug on those pieces to make them longer and thinner. The material will shed a little at this stage, but don't worry - it won't disintegrate!
When the pieces are fully stretched out, put a safety pin on one end of the first piece and thread it through the channel at the top, ensuring that there is an even amount showing at both openings.
Now repeat at the bottom. Tie the ends of both drawstrings with a knot to help prevent fraying and you are done!