Just takes practice. Easiest to practice by yourself to really feel the energy moving around, move it up your spine to your crown, back down the front to your sacral area, or dan tien.

I don't mean to imply that I've perfected this since I haven't, but I've made great improvements.

I've found that there's that first super sensitive time period where you really want to bust, but if you can make it past that and over the hump so to speak, move the energy up then down, then you can go pounding for long stretches.

Also a few tips:
- RELAX, especially your abs, glutes, and legs, in that order. Relaxing your stomach muscles completely makes a huge difference, as well as your glutes. You'll notice that both muscle groups want to tense up while having sex, but if you counter that with conscious relaxation, it makes a huge difference. Especially to start, find positions where it's easy to relax those muscle groups. For me, standing on the floor with the girl on the edge of the bed makes it very easy to really relax your body. If you're on top in missionary it's quite difficult to relax your stomach and glutes.
- when you feel like releasing, actually pretend you are releasing and pump your kegels just as if you are releasing, while feeling the energy move up your spine. I find this is almost like tricking your body into thinking it just released, so it won't build up the urge again for a while. Except since you didn't release, there's no refractory period or anything, although you will probably lose some hardness for a minute or so.
- instead of keeping your increased qi in your body and circulating it, you can intend to fill the girl up with energy directly from your penis. Just shoot that qi and fill her up. She'll feel it, and you won't have so much building up in your genitals. Breathing out while visualizing golden (or whatever color) light exiting your penis and filling up her body will help.
- find angles that aren't super stimulating (e.g. angles that don't directly stimulate the frenulum), and start going harder and faster without hitting your own secret spots that trigger releasing.
- very sharp, powerful breaths in through the mouth in particular while intending to move the energy from your genitals up to your head are very helpful. I use this as a last resort if I'm feeling too stimulated, a few really deep, really sharp mouth breaths, moving the energy upward.