I guess you are having premature ejaculation...Anxiety being the most common cause. So first try relaxation techniques and distraction method. Then try to cut down on any habits like alcohol, smoking or drugs. This will help delay ejaculation. If there's no improvement then you must be investigated for any comorbidities like
diabetes hypertension hypercholestrolemia. Treating these comorbidities also can delay ejaculation. Also any associated erectile dysfunction will also have to be treated. Medically there are many options like oral medications and topical creams. If the above conservative measure do not help kindly consult a psychiatrist for medical therapy...