Chemical & Rubber Aids to Stiffie Creation

As a 73 year old who has to take warfarin (a.k.a. coumadin) following open heart surgery, I suffer from the effects of having thinner blood than normal.
This limits my ability to get a full stiffie without other physical assistance, like restricting blood around the groin with cord, or introducing pressure on the prostate.

(UPDATE 6th June 2023: recently have been using a nurses rubber strip wrapped around the groin twice; the kind of thing that they wrap round your arm when taking blood; prior to that i used a rubber gym exercise strap, knotted into a loop and pulled into place on the lower back with the excess rubber being looped around the penis and testicles as many times and as tightly as you wish - these rubber solutions are not as uncomfortable (and tend not to leave blood bruises) as a cord around the groin and effectively constrict blood vessels over a greater area.)

So, in an effort to try to improve things 'chemically', I have taken to using L-Argenine (1000mg dose) up to 3 times a day.
Prior to using it on its own, I was using it with Pycnogenol, but was unimpressed by the effect compared to the cost.
I still use the mechanical assistance but find that my un-stiffie is longer and thicker and that when I do need to get stiff, it last much longer than before, so that edging is easier than it was. Hope that helps.