To dream that you cannot complete the sexual act is a sign of a feeling of impotence; the basic problem is that you feel a lack of enthusiasm and energy to face a situation. It is a symptom of laziness, of a negligence that will end up affecting your work and personal relationships. This episode is evidence that your ideals are very high, but you let yourself fall into comfort and easy options. The impossibility of connecting to your essence is detrimental to your creativity.
Reading in dream
Sometimes you will not be able to differentiate lucid dream. If you want to be sure, try reading a simple sentence, if you are able to read then you are in wakeful stage if not you are in lucid dreaming. Studies show that you cannot read while dreaming or you will not find the repeated sentences one more time.
Enhance your grades
Most of the kids, ages 10 to 16 are suffering breathing disorder when they sleep. It could be sleep apnea, snoring, and other kinds of interrupted breathing disorders. It's been said that students suffering from such have problems in terms of concentrating and learning, which can surely lead to a functional impairment at their school. Even college students who do not get enough of sleep at night have worse grades. Well, sacrificing sleep in order to meet some sort of deadline can be ideal, but depriving oneself to sleep will surely impair learning, which is not good for students.