How do SF 49ers superstars Frank Gore, Michael Crabtree and Patrick Willis stay relaxed before the Super Bowl? They hit up one of the BEST STRIP CLUBS on Bourbon Street!!!

TMZ has footage of the running back, wide receiver and linebacker hitting up the legendary Penthouse Club in the Big Easy last night ... a 3-level adult fantasy land.



You can spot Frank by his green beanie -- that he was wearing earlier in the day while hanging out with Crabtree and Willis at the team hotel.

It's possible the guys were just hungry ... because the Penthouse Club is famous for its "Naked Sushi" ... in which paying customers can eat raw fish off of naked strippers. Sounds appetizing.

Then again, we spoke with someone inside the club who told us there were roughly 120 STRIPPERS working the floor last night.

One source, very familiar with the strip club scene in New Orleans, tells us ... "Penthouse Club is the real deal ... but you have to be a baller in that place. That's a high-end spot."

Guess Chris Culliver won't have to worry about these guys in the locker room.