Clamping is really not necessary to obtain continued growth through traditional exercises. If it is utilized by a skilled practitioner it can enhance gains but if you do not have the requisite skill you can easily do serious damage. Your penis will retain blood with the same pressure it takes to hold a small bird; however, to create deformation as well as improving blood carrying tissue it obviously requires greater intensity. The problem is that “clamps” take this criteria to incredible thresholds and the non-skilled cocksman can incur an industrial accident.
Jelqing with wraps to retain blood is equally effective without the increased potential for injury. As a person moves through the PE regiment and experiences long periods without gains it then becomes necessary to “up the threshold.” Clamps are the equivalent of using a Cat backhoe to plant a tulip, the soft tissue and structures that form the penis can be manipulated very easily with far less stressful techniques. Stressing the cock is necessary to widen blood carrying tissue which in turn will allow the penis to hold a greater volume of blood (its all about volume).
The problem as I see it with clamps is that individuals really get carried away with the “quest.” And as a result they have severely discolored members, thrombosed veins, blown-out walls, and damaged valves that control erectile quality.