So I am on my third month using my LadyCup Large.
Despite what it suggested I should get because I am not over 30 nor have I had a child, I chose the large cup because I know how heavy my periods come each month.
Anyway, I fell in love with my cup as soon as I arrived in the mail and hearing all the stories of "you don't have to change it for 12 hours!" because of my frustrations with heavy periods. Well I got kind of discouraged because of the fact that on my second and third days (which are my heaviest) I was leaking. No exaggerated, murder scene, leakage but I was still disappointed because it told me I didn't have to change for 12 hours. :(
So I came to find lots of helpful tips on this website and other searches I came upon and it turned out to be the way I was inserting it. So after putting those tips together I think I finally have it!
Last night, which also happened to be my second day of my period, I inserted my cup before sleep and woke up after 10 hours of sleep (lazy, I know >.>) and guess what? No leaks!
Now this may get kind of descriptive, or TMI and I apologize for that. I'm just trying to help :)
I read on some random post that when inserting the cup, wherever the cup is folded it has to face down on your vagina because there is more room on the bottom part for the cup to pop open.
For example I use the c-fold because I find it the easiest, and to insert it I insert in like an "n" with part that will unfold facing down.
Also I do not shove my cup all the way in. I make sure that the cup is completely in and usually it pops open, but if it doesn't I push my vaginal walls so it opens. Next, I kegel it into place. Now I don't know if its because of my cervix moving but I found that at some moments after kegeling my cup was lower and today it was higher. Anyway after kegeling my cup in I give a little tug on my cup downwards to create a seal, and that's it!
So far I haven't had any problems with leaking. :)
I hope I am able to help some of you. Good luck and don't give up! :D