Here's a tip on quick and easy legwear for your lalaloopsy or other kind of doll:
Take a sock and turn inside out, then roughly draw on the shape of the panty with a ballpoint. You can use the elasticated band on the top to go around the tummy of your doll. Sew all around the contour, making sure not to make the legs too narrow. Then cut out but leave 0,5 cm all around otherwise the fabric will rip easily.
Now you just need to turn it back again and you have a nice piece of legwear for your doll.