To reiterate everything thats been said, there is plenty of time. Also keep in mind that just because Master B might not be something you talk about with your friends, when your in the field everyone knows that everyone is doing it and nobody really cares.
Wasn’t there even a saying or something-“You’re over-sexed and over there”, or something like that?
The British joke about US soldiers there was, approximately - Over paid, over sexed and over here.
A title to be proud of. 
To expand a little on my previous answer. The whole thing was: “There are only three things wrong with the Americans. They are over paid, over sexed and over here.”
And the Americans answer was the British were underpaid, undersexed and under Eisenhower.
To answer the OP the Army discourages any contact between troops very strongly. At home base its no big deal you have plenty of time to visit the outside world and meet others of the opposite sex. On deployment it can get tricky. Brothels are off limits do to the health problems ( and may not be abvailable anyway. Adultery and fraternization are punishable and prosecuted. Of course some find their way around it but it often causes discipline problems. However the days of open bathrooms like they have in Full Metal Jacket are gone for the most part. There is always some privacy available. I never heard of anyone being punished for assaulting themselves 
To answer this OP, the Army officially does nothing! (I guess they assume their soldiers are old enough to take care of this on their own.)
Unofficially, the Army (and other services) just turn a blind eye to things that they know are happening (like masturbating under the covers in the barracks, in the showers, soldiers getting together in motel rooms when on leave, sailors visiting brothels when in port, etc.). They know they probably couldn’t stop it completely anyway (your body gives stronger orders than any commander), and really, why should they bother?
In fact, the services do provide some services to prevent problems from this. They give out a whole lot of condoms to servicemen going on leave. Sailors are gathered for lectures before they arrive in port, and sometimes even given lists of which brothels are known to be unhealthy (“off-limits”). The services provide a lot of VD treatment to infected people, and this is medical treatment, it does not show up as a disciplinary infraction on their record.
Finding one partner is tough enough. Wouldn’t finding two be even more difficult?
Haj
Dang. I go looking for some porn, and you give me an actual arboretum.
Peace,
mangeorge
I’ll answer this one with this: When deployed to Kuwait and Iraq (and of course in the middle of no where, so forget a brothel) my friends sent me dozens of porn mags. I kept a select few for myself, and ran the porno libary. I got tired of Marines bugging me for all the porn, so I left in the middle of the hootch. Within 10 minutes all the magizines were gone.
In my experience, the Army was basically a giant boffing festival. To describe the male-female liasons that went on would take me four hours and a Powerpoint presentation of the most hideous spaghetti logic. You’re putting men and women between 18 and 25 together, and there’s gonna be humpin’. I wasn’t in uniform for 48 hours before I was handed a few doobs and told to be wary of the `ditch pigs’ (women in the infantry units.) I ended up sleeping with three female soldiers in just over four years of service, and I was an amateur.
Is it TECHNICALLY against the rules? Yes, it is. Does anyone care? Unless it causes an actual discipline problem, no.
My understanding is that, in the absence of women, the soldiers immediately turn to each other for comfort, and indeed, massive all-male orgies take place.
Oh, wait. That “documentary” I was watching might actually have been a porn flick . . .
Bloke in the nursing home I worked in regailed me with tales of how he’d never, never have used a prostitute while he was in the army in WWII. Went on about how filthy they were for some time. Then I got a five minute talk on how it was easier and more efficient to get a lieutenant to service you instead.
I only went in to change his bedpan.
Old Joke…
Soldier on a long tour in the desert goes up to his commanding officer and says “I 'm going nuts, I need sex now or I will crack up”. The officer says “I completely understand. Thats why we keep a camel in the stables there”. The soldier was shocked at first, but thanked the officer and went out. Five minutes later he came back in and said “Thanks, I really needed that”. The offcier looked puzzled and said “how did you get to town and back in that short time?”
Was this an intentional pun… or do I just have a dirty mind?
Soldier shows up for his first day of duty in the desert. His CO is showing him around the camp, pointing out the barracks, the latrines, the mess tent, etc. The soldier sees a barrel with a hole in the side sitting in the middle of the camp and asks, “What’s that barrel for?”
The CO says “Well you can stick your dick in that hole and get yourself a free blow job any day but tuesday.”
“Why not tuesday.”
“Tuesday’s your day in the barrel.”
Boy, it all seems so complicated…all this time I was under the impression that everyone just brought an extra sock.
Gasp!
Marines don’t look at porn. Not do they visit OLTAHFD’s.
I can’t believe it took this long before the first mention of the “victory sock”