The primary symptom of premature ejaculation is the inability to delay ejaculation for more than one minute after penetration. However, the problem may occur in all sexual situations, even during masturbation.
Premature ejaculation can be classified as lifelong (primary) or acquired (secondary). Lifelong premature ejaculation occurs all or nearly all of the time beginning with your first sexual encounters. Acquired premature ejaculation has the same symptoms but develops after you’ve had previous sexual experiences without ejaculatory problems.
Many men feel that they have symptoms of premature ejaculation, but the symptoms do not meet the diagnostic criteria for premature ejaculation. Instead these may have natural variable premature ejaculation, which is characterized by periods of rapid ejaculation as well as periods of normal ejaculation.