Jamie, I wonder if I can do that leaning on something other than a ball, like my couch? My other problem is that I do not have time to go to the gym and go to school, finish school work, and spend time with my kid, plus I'm too cheap to pay for a gym membership. Also the reason I stopped walking/running lately because it's WAY too cold to take a baby out for a stroll. Especially when he's too big to stay snuggled in a blanket.
But I have tried what you're talking about, Mariahh. I do that sometimes, but I mainly feel that exercise in the middle of my lower back and my ass cheeks. I learned it as you raise your legs up and criss-cross your legs 3 times, and then lower. That is not easy! haha! But I think I have started feeling a little doing these side-lunges and extending one arm above and letting the other hang so that the obliques/back muscles are doing all the work holding my body up. Maybe I'll just do a lot of that.