Through lots of experimentation (ooooh, ah, mmmm, and ouch) here's what works best for me...
First, the biggest mistake I made was trying to do everything at once. My body was used to certain things so the most important thing I learned was to take it one step at a time, wait, get used to it, then take the next. Being very worked up when I decided I was going to shave prevented this from happening several times. That night was a lot of fun, but work the next day, or just life in general sucked. Anyway, for me...
1. Cut with scissors / shears for a couple weeks. Get it as close as you can without pulling the hair.
2. Flip top on an electric razor - go over the area ONCE. Do that for a couple weeks.
3. The regular end of the electric razor - use new blades and go over it gently, ONE time. Again, a couple weeks.
4. Go over it a little bit more the next time you do it. Keep getting more hair off every couple weeks. Go slow and if something isn't getting cut do NOT force it. think about it and tackle it again the next time.
Before taking these steps, get some Bikini Zone or something similar and put it on every time after you shave.
You can do the same thing with a regular razor, but I'd suggest getting disposables and using a new one each time. Take the same first step as above. Then take only one swipe only each time. Wait a 3 or 4 days then do it again. As your body can accommodate it, increase the frequency and number of "swipes". Always put antibump cream afterwards. Always go WITH the hair for at least a couple months. Only when you get no bumps and all of the hair off you can going with the grain should you go against it. I know it's frustrating as hell. You're soooooo close. "if only I could go against the grain, it would be baby smooth". It will be but wait a few weeks. When you're ready, get very good disposables to use the first few times. ONLY one swipe per time, blah, blah, blah. Use very warm water, use PLENTY of shaving cream. Pat dry, don't rub, and use Bikini Zone. Baby power or Vaseline during the day helps as well.
It took a long time for me, but now I'm very smooth and it hardy takes any time. Just gotta keep up with it.
Best of luck!