I don't want to have sex anymore. Can it be prevented from getting erect?

Patient's question:

I am not married to my girlfriend, so I don't want to have sex, but sometimes I can't control it. Can it be prevented from getting erect? Thank you

Doctor's answer:

Hello, your idea is good, I've heard a saying, I'd like to share with you: The world is a great man, who can always control his own desires.