Why does it get soft right after entering during sex with your girlfriend when it was originally hard?

Patient's question:

Patient Gender: Female
Patient Age: 27
Hello, you have a condition where your penis cannot erect, or the erection is not firm, or it is firm but brief, making it unable to engage in sexual intercourse. The above situation falls under the category of impotence. You should go to the hospital to rule out whether it is impotence or phimosis.

Doctor's answer:

Hello, if you have difficulty achieving or maintaining an erection, or if your erection is firm but brief, making sexual intercourse impossible, this may be a symptom of erectile dysfunction. The above conditions fall under the category of erectile dysfunction. It is recommended that you visit a hospital to rule out whether it is caused by erectile dysfunction or excessive foreskin. If the foreskin is excessive, surgical treatment should be performed as soon as possible.