2d_animation animal_genitalia animal_penis animated anthro balls big_balls big_penis bodily_fluids consentacles cum cum_exchange cum_in_balls cum_in_penis cum_inflation cum_inside digital_media_(artwork) disembodied_hand duo equine_genitalia equine_penis erection expansion flipaclip_(artwork) frame_by_frame genital_fluids genitals growth henkeiusagi huge_balls inflation larger_male larger_penetrated long_penis low_res male male/male male_penetrated male_penetrating male_penetrating_male mammal nude penetration penile penile_penetration penis penis_in_penis penis_tentacles precum prostate sex short_playtime size_difference smaller_male tentacle_sex tentacles unusual_anatomy unusual_genitalia unusual_penis urethral urethral_penetration watermark what what_has_science_done