sportsherald. 2 votes Vote for this answer. Another name for a wing dam is a groyne: 'River groynes (spur dykes, wing dykes, or wing dams) are often constructed nearly perpendicular to the riverbanks, beginning at a riverbank with a root and ending at the regulation line with a head.
The foreskin (also known as the prepuce) is a portion of skin on the penis that covers and protects the tip of the penis, also known as the glans. It can be a tough world for a glans -- there's abrasion from undergarments, cold winter weather and dry air.
Let's cover some anatomy first so that you have the basics to work with. That should help you understand why you don't have to worry about how your foreskin is in regard to how far it sits back or with holding unto it during sex. Some of my answer will also address circumcised penises, too.