The fastest way is Nair hair removal cream! But don’t get it on your genitals!!! It burns. I wear a cotton thong panty when I use it to protect my genitals. You can use Nair all the way to them that way. As for razor bumps two things help with that. First a little sun on you bikini area works wonders to stop that! A little tan not a lot. Second they make Bikini Zone for just that reason. It works great if you remember to put it on regularly. But it leaves a sticky feeling on you!
Once you have gotten rid of the hair! The next trick I do is keep it off! When I shower I soap up my legs and areas that I don’t want hair. Then I take a razor and on my legs starting at the bottom I pull the razor up to my knee and without removing it push it down the same area, cleaning the blades I just did. Then move over and overlapping and start over again. When the hair is short enough you can get several swipes without rinsing the razor. I do that with every section I don’t want hair. It is fast and easy to do that way and you can do your all you shaving needs quickly. Well now you know what I do.