rule 34 4 arms animal genitalia antennae anatomy anthro arthropod arthropod abdomen backlighting brown body compound eyes countershading erection foreskin genital slit genitals hand on leg hand on thigh insect wings insects knot light lighting mandibles mantis markings multi arm multi limb nemesisilit nude penis presenting presenting penis red markings ridged penis shay gts simple background slit solo spread wings urethra wings 8033862