I have a new idea on how to attain lucidity.

Right before you go to sleep eat something with a humungous aftertaste that will stay with you that you can distinguish from how your mouth feels when there is no food. Remember that you ate that food. When you do a reality check think of the last thing you ate which should be the food with the aftertaste and see if the taste is still there. If it isn't you could be dreaming.

It has errors, but it is just another theory.