It is possible to have sex after taking Viagra orally and to regain an erection after ejaculation within the time frame affected by the drug’s effects. Viagra, a PDE5 inhibitor, works by increasing the blood supply to the penis to maintain a better erection hardness and to complete and maintain a satisfactory sexual life. Viagra needs to be taken orally half an hour before sex, and the effect of the drug usually lasts anywhere from half an hour to 2 or 3 hours. After this period of time with the drug, general stimulation after is penis are able to erect. But it should be noted that Viagra is not suitable for all people, must go to the hospital to clarify the cause of erectile dysfunction, and then under the guidance of the doctor standard use.