Hello, i'm 18 years 8 month old { male}. my question is does masturbation cause shrink penis and poor erection and premature ejaculation?

Sexuality: At age 18-19 sexual problems may be due to sexual and physical abuse, poor self esteem, use of alcohol and drugs, and failed relationships. Masturbation does not cause shrinking of penis, please see a therapist for coping with stresses improvement of self-esteem and sexuality.

No: All young men enjoy their bodies. It prepares you for adult roles and keeps you comfortable and able to focus on studies, work, and building relationships and skills. The first two are totally untrue and you should avoid people who tell lies like this. The one possibility is that if you do not have privacy and try hard to finish fast, you'll need to adjust when you have a partner.