Pretend to be a big titty onee-chan and wake the legs with ara-ara titty rub.
However, you don't need to suffer this. The reason why your legs won't move when you do, is because the signal didn't reach your legs yet. You can easily deal with this with self-hypnosis.
What you need to do is look at your clock, set a time to wake up, then lie down on the bed. Keep chanting what time it is and when you want to wake up. For example, if it's now 1am and you want to wake up at 6am, you can say, "It is now 1am. I will sleep for 5 hours. I will wake up at 6am." Keep saying it until you feel tired or drowsy. You don't need to focus on the words either, just murmur it if saying it aloud is a burden. What matters is you know what you're saying.
Sleeping on your back is easier to wake up, but this method can be done with any posture. It won't work at first and you will still need to rely on alarm clocks (set it like half an hour from the time you decide to wake up). But as you keep doing this, it makes it easier to self-hypnotize yourself. Try it every night for 1 month. Once you're used to it, you can only chant it three times like Ai-chan does.
This method has ensured that Ai-chan never woke up late (or woke up late or early by like half an hour from the decided time). Ai-chan has not used alarm clocks since Ai-chan was 20. Ai-chan wish Ai-chan knows this method when Ai-chan was in school.