All stretching?

Hey guys, I have a question. It seems like when I do my flaccid stretch, it’s exactly as long as my hardest erection can get in length. Also when I get a full erection.. my penis literally goes straight up, and I can’t bend it down past a 45 degree angle. I think all these signs point to my ligaments are holding me back quite a bit. Is it possible to get good gains doing pure stretching (the methods just pulling with your hands, no jelqs, or if any jelqs, not many at all), and if so, what would be a good routine for just stretching, or just a routine to work on stretching my ligs? Thanks guys

A routine which consist regular stretching, JAI stretches, inverted v stretches, helicopter stretches and tendered stretches like my routine will work, at least it works on me:) .