rule 34 2021 animal genitalia animal penis anthro arm support ass back muscles balls black sclera canid canine canine penis canis claws erection fangs finger claws fur genitals knot licking licking lips looking at viewer looking back male mammal monochrome muscular muscular anthro muscular male nude patreon penis perineum presenting presenting hindquarters quads raised tail rear view sharp teeth shower showering sketch solo standing teeth tongue tongue out triceps vein veiny penis water wolf xuan sirius 4587271