Rule 34 Dev - anthro echidna erection fur genitals hands_behind_head hi_res humanoid_genitalia humanoid_penis knuckles_the_echidna male male_only mammal monotreme muscular muscular_male pecs penis purple_eyes red_body red_fur royer27_xd sega simple_background solo sonic_(series) sonic_the_hedgehog_(series)|6678237208