Some men might even orgasm to the flowing water alone- I never have. Once your raging member is throbbing contentedly, stand up, wash some if you wish, and then once you get soft, start in with the soap action and masturbate with your hands. There's other techniques, and if you have a removable showerhead you have even more great things to try. Again, experimentation is the key, just make sure what you think of trying isn't something that will get you hurt. The anus is a very sensitive area, and stimulating both these areas can lead to some really explosive orgasms that could even rival the females.
Vibrators have even more uses.
Men can be as manly as they want outside the bedroom, but lets face it, we're all big puffy teddy bears when it comes to sex. Don't let false and misinformed inhibitions prevent you from something you might end up loving. As I said before, combining anal stimulation with masturbation can lead to some truly amazing orgasms. In addition to stimulating your anus, if you're into anal sex at all you might want to consider getting off with a couple fingers inside your anus. Be sure to lubricate them well, with a water based lubricant first.