Originally Posted by Priapologist

Sorry, being new here I didn’t realize how much of this stuff had already been discussed. Forgive my redundancies. Anyway, yes, the mechanics of LOT make sense. I have made some diagrams to help explain my take on it. The first just explains what everything is, the second shows a 12 o’clock tug and the effects of the pubic bone and the triangular ligament (I’ve left the fundiform ligament out of these diagrams for clarity), the third shows a 9 o’clock tug, and the fourth shows a 6 o’clock tug. There is embedded text to explain each figure. Also, these figures are schematic and, hence, are relatively anatomically correct.

The figures diagram two extremes based on six variables: high pubic bone angle versus low pubic bone angle, high ligament attachment versus low ligament attachment, and tight ligaments versus loose ligaments. The pubic bone angle is based on a reasonable variation in pelvis morphology among men. The diagrams are of the extremes, and any combination of the six variables is possible.

The principal muscles acting during the tug are the ischiocavernosus (IC) muscles, which connect the crura to the ischiopubic rami. These pull the penis straight back under the pelvis, but are normally used (involuntarily) to slow blood escape from the penis, making a stronger erection. Exercising these muscles will develop a stronger wood. This isn’t a Kegel, though. Kegels are contractions of the pubococcygeus (PC) muscles, which are part of the levator ani muscle group (try to keep from farting – that’s your PC muscle in action). These are the muscles that a guy’s partner (boy or girl) should exercise, to get a nice, tight grip on his wood. So called ‘reverse Kegels’ are contractions of the bulbospongiosus muscle, which wraps around the bulb of the of the corpus spongiosum. Exercising this muscle will improve an erection and give more powerful ejaculations.

Why are IC muscles important in LOT scoring? The IC muscles pull the corpi cavernosa more or less straight under the pelvis. When an IC muscle is contracted, it creates a force vector. The penile shaft responds to that vector in several ways, depending on the aforementioned six variables. In the 12 o’clock position, the penis is pulled around the pubic bone at the symphysis, which acts like a fulcrum point. Contraction of the IC muscles causes a response vector in the penis that follows the curve of the pubic bone. To a first approximation, we can say that the response vector is downward, and you see tug back. At the 9 o’clock position, the penis is minimally affected by the pubic bone, but is still affected by the qualities of the ligaments. Low, loose ligaments will result in little impediment to tug back, and the response vector will roughly parallel the force vector. High, tight ligaments will pull the penis up and anchor it more strongly, resulting in a response vector that is not parallel to the force vector (see diagram). At the 6 o’clock position, ligaments affect the response vector regardless of their description, but, the high, tight ligaments will bind the penis in such a way as to negate the force vector: loss of tugback. Comparatively, the low, loose ligaments will bind the penis only modestly, and the response vector, while modified (diminished force), is still sufficient to be seen as tugback.


Interesting with great pictures:
Priapologist - LOT question