dtwarren1942 wrote:You are probably referring to the suspensory ligament which is very tough and difficult to streatch.
There is an operation that cuts this ligament. It lets the penis stick out further giving the illusion of more length. The fact is that the penis is free to extend out further, so, yes, greater effective length.
However, this is at the expense of some effectiveness at pleasuring your partner. With this ligament severed, the penis has little to make it stand in an UPWARD direction, or to let you "pulse" your penis inside your partner by (the Original Poster's suggested technique) pulsing your abdominal muscles (particularly Kegel and anal sphincter).
Note that what I have posted above is not by experience, but from what I have read on the internet from medical journals and from casual sources. Best to verify anything before you accept it as true, but now you have directions in which to search.