That pent up sexual frustration has to get out somehow. Personally I made myself a rule that I'm only allowed to masturbate to non-deviant stuff, as in; no real porn, only a pic of a hot girl and my imagination telling me that I'm having dick-in-the-pussy sex with her. If I'm having trouble getting excited for it, I just imagine a little bit of fetish stuff to get me up again and then switch back to puritan-mode once I can reach orgasm with no assist. It helps me in keeping my cooming to just once a day and makes me less degenerate and more well-adjusted in the process.