Refers to foreskin being unable to be drawn back over the widest part of the glans due to foreskin tightness. Most of the times, it is associated with excessive long foreskin that contains an abnormal amount of fibrous scar tissue.

Phimosis may cause urinating difficulty, pain and difficulty during masturbating, erection and sexual intercourse. Circumcision is the usual way of treating Phimosis. 

Paraphimosis

Paraphimosis is a constriction of the penis behind the glans, due to extremely tight foreskin.

The cause arises from inflammation and narrowing of the foreskin which resulted from poor personal hygiene. Or it can be the result of the tight foreskin is drawn back to expose the glans during sexual activity and is not pulled back over subsequently. 

The symptoms includes painful swelling at end of penis. Treatment is to compress the penis head while forward traction on the foreskin is applied. If not, prompt surgical intervention (circumcision) will be necessary. Whichever, medical help is required.