Viagra certainly produces an erection but the headache and body/back ache the next day was almost crippling for me. I also had the "blue" vision and bright sunny days were terrible. shades were a must. I did not notice a thinner erection, but have a thick cock..
tadalafil/Cialis works much better for me. minimal side effects and more natural. lasts for days. and I'm ready when she is ready. I do notice that I carry myself fuller, bigger bulge. I take a low dose several times a week.
have used avanafil also. it's very fast acting. about 5-10minutes after taking it, your stomach will "growl" and you can feel yourself "twitch" down there, and a massive erection soon follows. I have used this with my low dose tadalfil, and have quite a few erections over the next 24 hours much to the annoyance of my wife, who is not that interested in much sex at one time anymore. the problem is affordability (for me)....cheap avanafil is not easy to find, as are honest, reliable sources.