Hi, I can understand your concern for lose penis and fast ejaculation during first time intercourse. In most of the cases this is due to anxiety related issue. Both erection of penis and ejaculation are controlled by our brain. So if you have one thing or the the other thing in your mind which is creating any type of stress or anxiety then the vigor and the excitation is not felt. The same is true for ejaculation also, where due to anxious state the peak point reaches early and the control is lost. Relieve your anxiety of any type and keep yourself calm. Don t take any kind of medicines as can harm you in long term. A very specific point is to have safer sex by using condoms by yourself and dams by the partner in any type of sexual activity to prevent any type of sexually transmitted disease. Take care.