Now, the penis is erect but the next challenge is to make sure that the erection lasts for a few hours. For this, the level of PDE5 (phosphodiesterase type 5) in the body decreases. But why do we need to suppress PDE5? This is because PDE5 is a chemical that acts as an erection after ejaculation of semen. When very small amounts of sidalist strong 140 mg PDE5 are present, the erection reduction process takes longer. Thus, the erect penis lasts longer and even after ejaculation.