(1) Threespine sticklebacks are laterally compressed, fusiform shaped fish with three sharp, erectile spines at the forward part of the dorsal fin.(2) This drug increases the flow of blood in the erectile organ which enhances the chances for a much better erection.(3) Tadalafil relaxes the blood vessels and the muscles which are present in the erectile organ.(4) Also distinguished by their long, erectile , iridescent tail feathers, which they spread at every opportunity(5) Its blood-filled organ, encased in collagen, is remarkably similar in structure to the mammalian erectile penis.
