I certainly say practice makes perfect ...
Apropos I read recently that the average female takes 20 minutes to get aroused enough to trigger an orgasm ... which means many take a lot longer, of course ... poor things, compared to the average male, that leaves a lot of teased pussy around waiting for a long-lasting dick to finish them off. As the article said, 20 minutes is enough time for the average male to get aroused, cum, and recover for a second shot
I totally agree with thick condoms, definitely delays my performance.
The issue I see with artificial methods - be they chemical or physical aids - is they are all ultimately reduced in effect unless you get to the root cause of your difficulty. That means the only ultimate fix is a mental one.
If you don't already, I suggest you get into DATY or build a great massage technique (for her) - and make a point of pulling out on a regular basis to give your dick time to rest. Doesn't matter if you go limp, keep working on her and you'll soon get hard and start again, just make sure you're pulling out and keep working on her arousal.
OK it's hard to do with a WG who's hell-bent on finishing you just as quickly as she can
but that's part of the game ... keep control!
BTW another intriguing observation I noticed is the more I try to allow myself to cum the more it gets delayed ... whereas if I try to hold back it just explodes out, if instead I relax and try to push the stuff out early it gets bottled up and waits a bit longer. You could try that