Adult Swim star Eric Andre partied so hard his clothes fell off -- the comic pulled out all the stops and threw a ballin' 32nd b-day bash at a kitschy desert trailer park hotel.

Our party sources tell us the wacky host of "The Eric Andre Show" bared it all in the hot tub during the Joshua Tree soiree. No other takers, apparently ... but it was his birthday, after all.

We're told Eric plunked down about $2,500 to rent the entire Hicksville Trailer Palace -- a hipsterific getaway in the California desert... with 9 funky themed trailers. Eric's booze crew included fellow comics Tom Green and Felipe Esparza.

Entertainment included BB guns and Mexican food all night long -- and in the morning ... pancakes and scrambled eggs for everyone.

Hold the nuts.