Here are instructions to make a bblp warmer for those cold winter days and nights! The cover should be made out of fleece or wool so that any pee that gets on it will be repelled off (otherwise you might have to wash it each time it is used!).
Download pattern. Some download times are long. Tape section 1 to section 2 and section 3 to section 4. Then tape section (1+2) to section (3+4).
On the pattern I stated the lengths of the elastic needed but that was when I was using a fairly thick wool fabric and when I made this one out of fleece I need to make the bottom elastic shorter to achieve the correct shape around the top of the potty, therefore, before you cut your elastic, thread it through the bottom and try it on the potty to make sure the top opening rests just along the the back and doesn't cover the bowl area.
On the pattern I stated to put the short edge on the fold so that the seam would end up in the back of the potty, when I made this one I wasn't paying attention and I put the long edge on the fold. No matter, this just leaves the seam in the front! Either way it still works:)
Placing the short edge on the fold, trace and cut out your pattern. Fold right sides together and sew a straight stitch seam (1/4" seam allowance) along the open edge.
Hint: If you are having trouble drawing your pattern on fleece try using a washable crayola marker.
UPDATE:
I found it much easier to put a drawstring and toggle instead of the bottom elastic. By placing the toggle at the back of the potty I can tell where the bottom is and which side is the back. I can also tighten the drawstring to ensure that the top opening is wide enough.

