I tried it for a while but it was quite possibly the most painful experience of my life! I've waxed my legs for the past 4 years but it's not even comparable in terms of how it feels. From my personal experience, I'd say you have to be quite tough to be willing to wax downstairs. However, the end results are much nicer than shaving so it's worth it if you have a good threshold for pain - unfortunately I don't.
If it says bikini area then I'd assume it's okay to use. Any waxes I've used have always specified "bikini" "face and bikini" "legs" etc. I tried a few different waxes and found Parissa Wax Strips to be the best for down there, especially on sensitive skin. You can easily get them in boots I'd imagine. They're the best ones I tried that have a cooling balm to help calm the skin, and they're a small size which make it easier! (if you're looking for a good brand at the moment I'd recommend them).