Phimosis can range from a tight foreskin that is difficult to retract to expose the glans (head) of the penis to pinpoint phimosis where the foreskin cannot be retracted at all. Men who have never retracted their foreskin is prone to phimosis as the foreskin forms adhesions to the underlying glans of the penis.
Erectile dysfunction is a condition where a man is unable to maintain an erection strong enough for penetrative sex. Some men with ED also complain of erections not hard enough for satisfactory sex.
Phimosis is usually not associated with erectile dysfunction. However, the foreskin can also be so tight that the man is unable to achieve an erection good enough for penetration. In this case, he should see a urologist to determine if the foreskin is indeed the physical limitation.