Click to help a sixteen years old boy.

I need help! I found this place because after a masturbation, I decided to make a change.
I was an overweight, undisciplined boy.. so let's get right to the point, here are two examples...
1. whenever the night before a school quiz, since I never do my daily review on academic work, it's easy to get desperate about the quiz and the first thing I think of is masturbation ......
2.(just a minute ago) reading a philosophy book that interests me a lot and which I believe will help me a lot, but the words bore me, once again ...... Masturbation.
After two minutes of excitement, I had to face my life of failure again ....
Help, I do think I could be much better if I could quit this stuff ......

a thread on Reddit about a 2003 Chinese study which claimed that men who refrain from masturbation for seven days experience a 145.7% spike in testosterone levels on the seventh day. [copied from Wikipedia]
If you've studied biology before, you'll know that testosterone is the key to being productive/optimistic/tough.

Please suggest some very direct ways for me to actually start stopping this bad habit..
Thank you very much!!