Adjustable Constriction Loop Some men are able to naturally get an erection but find that their erection does not last long enough for satisfactory intercourse. This is often due to a condition known as venous leak. Many of these men can be helped with the use of VenoSeal. VenoSeal is an Adjustable Constriction Loop that is placed and tightened at the base of the penis. With proper tension, the VenoSeal device will be comfortable to the user but also provide enough additional pressure to prevent blood from flowing back into the body, thus maintaining the erection.