Rule 34 Dev - balls bodily_fluids duo erection genital_fluids genitals kneeling licking male male/male multi_eye not_furry nude open_mouth oral penile penis penis_lick saliva sex tongue tongue_out nsg_editor black_mesa half-life valve alien human humanoid mammal vortigaunt 3d_(artwork) digital_media_(artwork) source_filmmaker_(artwork)|17939304355