Cut the sleeve material square, hold it between two fingers so it doesn't expand, slide it back slightly from the desired end, add a small drop of super glue, slide the sleeve back to where it should be and hold it for a couple seconds to allow the glue to set. Be careful you don't glue your finger to the sleeve. Not that I would know anything about that first hand.
If you did it correctly, the end of the sleeve material should be inside the dress-up kit and/or pump cover so the actual end of the sleeve is out of sight. The glue holds it in place keeping it from fraying and splitting.
Edited by Questors - 2/12/16 at 5:49am