Masturbation Benefits 

It is held in many mental health circles that masturbation could relieve depression & lead to a higher sense of self-esteem. Masturbation could also be particularly useful in relationships where 1 partner wants more sex than the other – in which case masturbation provides a balancing effect & thus a more harmonious relationship.

Mutual masturbation, the act by which 2 or more partners stimulate themselves in the presence of each other, allows a couple to reveal the 'map to pleasure centers'. By watching a partner masturbate, 1 finds out the methods they use to please him- or herself, allowing each partner to learn exactly how the other enjoys being touched. Intercourse, by itself, is often inconvenient or impractical at times to provide sufficient sexual release for many people. Mutual masturbation allows couples to enjoy each other & obtain sexual release as often as they need but without the inconveniences & risks associated with sex.

In 2003, an Australian research team led by Graham Giles of The Cancer Council Australia found that males masturbating frequently had a lower probpower to develop prostate cancer. Men who averaged five or more ejaculations weekly in their 20s had significantly lower risk. However they could not show a direct causation. The study also indicated that increased ejaculation through masturbation rather than intercourse would be more helpful as intercourse is associated with diseases that might increase the risk of cancer instead. However, this benefit might be age related. A 2008 study concluded that frequent ejaculation between the ages of 20 & 40 might be correlated with higher risk of developing prostate cancer. On the other hand, frequent ejaculation in one's 50s was found to be correlated with a lower such risk in this same study.

A study published in 1997 found an inverse association between death from coronary heart disease & frequency of orgasm even given the risk that myocardial ischaemia & myocardial infarction could be triggered by sexual activity.
Masturbation Answer above is based on work by authors at wikipedia.org. Text above is available under Creative Commons Attribution-ShareAlike 3.0.