Anyways, I believe that the best way to learn how to do things is in baby steps. I play the clarinet, and I know that you can't just look at a difficult piece of music and play it perfectly right from the start. You have to develop some muscle memory in your fingers first, starting slow and gradually up until the piece of music is now so easy you wonder why you ever thought it was hard in the first place. Using a cup is the same way. Since you've never had anything in your vagina before, it naturally is going to be awkward the first time.
So I thought up a set of baby steps to introduce myself to the cup, and I'm going to share them here. These steps are going to seem small and insignificant, but hey, that's why they're called baby steps :) If you can do more then one step at a time, then do so, if you are ready. But if you feel any discomfort, wait until later to try again. You will be able to get the same step you were at before, because the muscles will remember how, and then you will be ready to go on to the next step.
Before your period starts
1. Find the entrance to your vagina. This sounds stupid, but I honestly thought it was higher than it really is.
2. Relax, and try to stick a finger in. Just a little bit. Enough just so you get used to having something in and out of your vagina.
3. With one finger, try to reach as high as you can inside of you. If it hurts, then stop and try again later.
4. Once you get good at all that, explore your anatomy. Feel where your hymen is, and stuff like that.
5. Stretch your hymen a bit. Put some pressure on it with a finger, but not so much it hurts. You can also try putting more fingers in, but I never got to that point.
When you're on your period
1. Explore your anatomy more! When I'm on my period, I'm a lot looser and my hymen is more flexible.
2. Now get your cup out. Decide which fold you want to use. I like the 7 fold best, because it's small and easy to hold onto.
3. Now, separate your labia, and put the tip of the folded cup at the top. Move it downward towards your vagina until you feel the opening. I found it was tricky to find it without actually touching it with my hand, but it gets easier with practice.
4. Try pushing the cup in. Make sure you are aiming for your tailbone! At first I wasn't, and it hurt! Put the cup in a little at a time. If you have discomfort, stop and try again later.
5. Eventually you will be able to put most of the cup in, but don't put it in all the way yet. Practice putting it in most of the way a couple times.
6. At this point you should be able to put it in all the way. It's a little tricky to tell if it's open. Running a finger around the edges helps. The first time I put it in, it didn't hurt at all. In fact, I could hardly feel it.
7. Okay, now that you've got it in all comfy, just get it over with and take it out. This is the hardest part. Make sure you're relaxed. The first thing want to do is stick in a finger, and break the suction by pushing in on the cup rim. Then bear down, and twist it out. OK, I'm not gonna lie, it hurt because my stupid hymen was in the way. I'm not sure if I tore it or not, because I can still feel it there, but it's less in the way now.
Whatever you do, don't panic about getting it out. If your hymen is in the way, just remember that it's temporary and won't keep the cup in forever :)
UPDATE: More removing tips!
So, apparently my cervix is quite high, even on my period. So when I tried to take my cup out after my first full day, I had quite a shock! I could hardly reach it, and it was slippery because the cup had started leaking. So the natural thing to do was, of course, panic. But I did manage to get it out! First thing I had to do was squat and bear down, really hard! It does move down when you do that, even though I was freaking out! Anyways, eventually I was able to get in a finger to push in on the side of the cup and break the suction. Then, I pretty much just grabbed it and pulled it out, while bearing down.
It didn't hurt that time, but I highly recommend doing it in the bathtub or shower, because I got blood everywhere, but thankfully I could just turn on the tap and wash it out.
Here are some tips if the cup leaks. At first mine didn't leak, but once I got adept at inserting it, it starting leaking. However, it would only leak for about half an hour then it would stop. Turns out I wasn't putting it high enough up. It would eventually move up on its own and stop leaking, but it's much better, at least for me, to put it up higher in the first place. It also pokes me if it is positioned wrong. So, if you have leaks, experiment with where you are putting your cup. You might even want to try different folds, as that might help position it properly.
Anyways, I think the most important thing about using a cup is not to force it in. Make sure you are ready. It's unacceptable for a guy to force something in you, so you shouldn't force anything in you either!
Also, remember that you will be able to get the cup in eventually! It WILL fit. The vagina stretches beautifully! Anyways, I hope I was helpful and didn't bore you to death!