Nude Dog Rescuer -- My Lungs Were Collapsing!

We barely noticed Eric Nies with his clothes on in New York yesterday -- but the "Real World" doggy rescuer claims he's used to getting naked and jumping in freezing cold water because he frequents bathhouses ... no, not that kind.

Eric Nies: Click to watch
The naked pooch rescuer finally explained why he felt compelled to strip down and save his friend's dog -- then he showed off the best way to raise your body temp after diving buck naked into freezing water.

Eric Nies: Click to launchAnother way to raise your body temp -- check out the photo gallery.