Do boys open their mouths when trying to appear bigger to another boy.? (No hissing involved) nubby was sitting in the cool side, but he was a little warm. Not overly toasty or anything. Anyways I took him out and immediately, toothless started showing his ass in his tank and Nubby crawled up my leg -- more like wiggled up it -- and Everytime toothless runs back and forth to head bob, nubby wiggles his tail, puffs up and just opens his mouth a little bit for a few seconds and then closes it. Is he just as weird as I think he is.? He isn't showing any symptoms of anything, aside from being territorial and wanting to mate.