anal anal_penetration animal_genitalia animal_penis anthro balls bambii_dog bdsm big_balls big_dom_small_sub big_penis bondage bound canine canine_penis cum cum_in_ass cum_inflation cum_inside domination duo erection fish humanoid_penis inflation internal knot male male/male male_domination mammal marine muscular muscular_male nipple_piercing nipples pecs penetration penis piercing precum scar shark size_difference submissive submissive_male vein