Crunchy sounds what you are talking about is due to the nitrogen bubbles in joints. Not a problem.
As per the books of forensic medicine" masterbation is a perversion" and compulsive masterbation is a disease which needs counseling and treatment. At this age you are bound to be aroused by so many stimulii, try to find out and avoid e.g. Watching prone, continuously thinking about sex, going to places where you are aroused must be avoided. Don't remain alone, increase your social involvement make more good friends and give your time to them, spend more time in public. Engage your mind in other things. Some simple measures like exercise and meditation
may help. But still if you are not able to overcome the problem you must consult a physician. We can add medicines also to support you. Regards.