Early ejaculation is normal, and very common, among men of all ages, particularly younger men. Premature ejaculation occurs when a guy “cums” earlier than either partner desires. There is no required or perfect timetable for ejaculation – it depends on the partners and on the particular situation. Sometimes it’s advantageous to have sex quickly – for example, when a roommate is expected home soon, or time is limited for other reasons. When a man masturbates and has limited privacy, speed can also be a real benefit. However, what works well when you’re by yourself may not be ideal when you’re hot to hook up with a partner.