In the past couple of months I've moved away from trying to get 2 pops in an hour and instead gone for one big one.
Generally the first pop would be embarrassingly quick and the second would be a struggle to attain.
Try some or all of these to delay the eventual:
1. Don't abstain for 3 days before. If you normally wank daily then have a wank the day before as usual. Probably better to still abstain on the day itself though!
2. Foreplay and lots of it. If you feel yourself getting too excited then go down on her for an extended period, leave your cock alone until it starts going soft.
3. When you do eventually get in, know which positions and angle of attack give you least stimulation.
4. If required, stop and change position. Try and delay re-entry if you need to cool down
5. Find a rhythm, just banging away is guaranteed to get you to pop
6. DO NOT picture your cock nestled comfortably in that hot, pink, juicy, delicious pussy.
7. Experiment - find what works for you
8. Relax and enjoy all of it. You're on a journey not a race
Personally, I find that after 15-20 minutes my cock goes almost numb and I can then shag away and cum only when I decide to let the desire and feeling overcome me.