We loved arms, had to move to bum because the arms needed a break. I would like to have more variety, but I don't want to waste a sensor trying. We tried on the stomach and the sensor fell off after 10 minutes. Regardless of where it is I always have to tape it down right away or it will fall off. Has anyone had luck using thighs, or anywhere else with little kids? I just wanted to find out what others are having success with.