'Brokeback Bachelors' -- NAKED Showers Together … But NO Sword Fights

The so-called 'Brokeback Bachelors' – aka JJ and Clint -- may not be gay, but they do enjoy water sports ... as in showers. Naked. Together.

As we first reported, the new ‘Bachelorette' promo baits viewers into thinking the guys are hot for each other ... even though they're straight. However, sources on set tell TMZ the alpha males did have a bromance because they’re ex-athletes who dig locker room style showers.

We're told JJ and Clint frequently took advantage of the mansion's communal shower ... and bro'd down with soap and suds. Yes, they drank beers together ... IN THE SHOWER.

We're told that's what led producers to ask the guys strategic questions ... intended to build up the 'Brokeback' plot. As we told you, JJ and Clint are getting a kick out of all the attention they're getting now.

It’s all fun and games until the hot water runs out.