This is a very kid friendly sewing project, and start to finish only takes about 20-30 minutes. Apologies in advance as to the quality of these photos for they were taken with my phone while I sewed in bed. I only have two excuses for this.
a) I was lazy and b) I was pretty lazy
First, you need the bottom of those jeans, that are now a cool pair of shorts. The pants I used were a size 8, super skinny. They had a touch of spandex.
Next, sew it into place using a basic stitch, being careful to sew just the cuff and ribbon together and not to the pant leg itself. Neatness doesn't matter here as the stitches will not be seen.
At some point you may acquire company. You will persevere none the less.
Next you will roll the cuff up once more. Now that sewing job you did is on the inside of the cuff.
Make a finishing stitch to this side, being sure to sew the cuff to the pant leg. I chose some nice wide x's. Repeat on the other side.
Now your top is done. It's time to finish with the bottom.
Line up a water bottle to your tote and roll up the bottom of the leg so that it becomes the same length as the bottle. At least three rolls up is suggested. If your pant leg is too long, cut off some of the bottom before rolling it up so that your cuff won't be too bulky.
I took one end of the ribbon and tucked it inside the seam.
Next, I opened up the bottom of the leg all the way and pulled the ribbon along the opening to measure the circumference (i say measure, but i did nothing of the sort).
Complete the bottom using the exact process as you did with the top cuff.
Folding up here. Finished with the same wide x stitch as used before.
And, with water bottle tucked inside.