rule 34 animal genitalia anthro barbell piercing blue eyes canid canine canis ear piercing ear stud erection full length portrait fur genitals green background grey body grey fur hair humanoid genitalia humanoid penis hybrid genitalia hybrid penis industrial piercing lying male mammal narrowed eyes nude on back penis piercing portrait pupbii purple body purple fur purple hair purple penis sheath sheathed humanoid penis short hair signature simple background solo three quarter view white body white fur white sheath wolf 6781617