You are doing everything right. Keep doing exactly what you are doing, with a bit more patience. It is common to feel these sensations in two or three waves before you finally enter the dream. Don't be fooled if the sensations suddenly stop, and you feel completely awake. Don't give up or get disappointed. Keep doing what you were just doing, and they will return quickly. Bounce back and forth a few times, and you will end up in a dream.