To work your abs using a noodle, simply place the noodle behind you as if you're going to rest on it, bring your legs up, toes pointed. Now you're going to bring your knees up to your chest, and extend, up and extend. This can also be done on the side of the pool, up, extend, up, extend. This works your abdominals as well as your legs. Let me show it to you from the side. Lean back, toes pointed, up, extend, up, extend. Enough of these and you'll be ready for bikini season in no time. Make sure to bring your knees up as far as you can go.