I bought one recently and have just finished using it for the first time. I tried it out before my period to see if I could find the right position, having read through the book and advice on the internet three times. I can get it in OK, but although I've done everything I'm told - tried different folds, cut the tail off to almost not there, positioned it lower, then highter, checked it's opening, turned it, squeezed it with my muscles, etc., it still leaks a tiny bit, so I still need a panty liner

All I can think is that I need to improve my pelvic floor muscles, so I'm working on that over the next month to see if there's any improvement. Once I get that problem sorted, I'm sure I'm going to be very happy with it.
Bit annoyed with DD1, though. She brought up the subject of periods so I took the opportunity to ask her if she'd heard of Mooncups and told her I now had one. I was going to offer to buy her one, but she reacted like I said I have a fetish for eating vomit or something

I mean, OK, so she doesn't fancy it, but she completely over-reacted. Oh well, I guess that's what being 15 is about.
Jinwin, I'd give it another try before your period 'cos playing about 'down there' later on might be a bit messy.

In the shower's a good place to practice. Remember to relax and aim for the small of your back, not the top of your head. I'm sure other more experienced users will give you better advice than I can though...