rule 34 2023 animal genitalia animal penis anthro anthro on anthro anus biped black claws blue claws blush canid canine canine penis canis claws digital media artwork duo erection fur genitals green eyes green tongue grey background grey body grey fur grey perineum hi res horn interspecies knot machine male malemale male on bottom male on top mammal on bottom on top pawpads penis perineum protogen purple body purple fur simple background teavern tongue whiskers wolf 7242113