What could happen if i take viagra (sildenafil) and add nitric oxide?

Here are some ...: While nitric oxide has been celebrated as the miracle molecule in medicine for its vascular relaxing effect, and studied and tried in treating pulmonary hypertension, its use in ED is still unclear. Yet, the "ending" product of PDE-5 inhibitors such Vaigra happens to be nitric oxide, which is known to relax smooth muscles inside sponge bodies of the penis so to enhance natural erection for ED...