rule 34 artist name barazoku chest tuft claws clothing domestic ferret erection gay genitals gradient background greyscale halftone hat headgear headwear hi res line art looking at viewer male male focus male only mammal monochrome muscular musk mustela mustelid musteline overweight pecs penis simple background sinibun 95 smile solo tongue tongue out true musteline tuft underwear vein white background 6143297