I've had luck while in the German FKK with a pill called
Dapoxetine. It's not approved in the US but it has approved in the several EU countries. I'm not sure if this is the kind of trick you are looking for but it was very effective for me at half the dose. Of course you should check with a doctor before taking any pills.
I've been working on my Kegel exercises in perpetration for my HK trip. Hopefully I won't need the pills this next time.