hsarge, I would keep increasing the intensity as you advance on your Penis Enlargement journey and by this I mean use more force on the stretch and apply the reverse kegel if targetting the ligaments. Unlike dld I suggest that the user feels the ligaments on each stretch and that the 'burning' sensation be something to aim for, as you know that you are really getting the maximum stretch possible, that is a fact based on the penis anatomy and to read more see the article section, as the burning sensation is sent out to stop you damageing yourself from going further with the stretch.
DLD is right aswell, that many stretch and dont feel it after regular work and still gain but my advice and ways of training are to go towards that feeling. Check out my V-SES stretch for more on how to really isolate the suspensory ligaments like nothing else.
If your not feeling the ligaments than imo your not stretching them enough. Its like with a footballer before a match stretching his legs, he knows that he has to stretch so far to really feel the ligs and when to stop, that feeling doesnt go away .. if it did than guys would be doing the splits and not know they were doing it.