I think I just invented / reinvented a fold that works better for me than anything else I've tried so far, and wanted to see if it's useful for anyone else. I think it pops open easily (for me at least) and has a more uniform profile down its length than some folds. Does it work for you?
The LABIAL FOLD: a double punch-down
General Description / Divacup and Lunette Instructions
Do this with two hands (I had to hold the camera): hold cup in one hand and with the other, pinch a corner of the cup and push down towards about the middle of the opposite side, much like the punch down but with an extra fold.
From the top, you get this disturbingly "labial" shape...
Squeeze the sides together to hold it all together, like this:
Top view (On a Lunette, only the outer folds would be visible, and the tip can be made more pointy.)
The basic method is the same, but the folding proportions will be somewhat affected by the Mooncup's thick rim. Sorry about the crappy photos; I had to use my phone because my camera died the night after I took the originals.
1. When punching in, punch all the way to the bottom of the cup:
2. Scrunch the cup so that one of the "labia minora" crosses over the other:
1)I should add that if you get it just right, it is possible to maintain the fold squeezing near the base (under the bulky part) without popping open prematurely. Then you can use the other hand to squeeze the tip smaller for initial insertion :-) after which the vaginal muscles help to hold the fold together until you let go.
2)Popping open: depending on when and where you let go, the cup may not pop completely open right away. If this happens, flexing the muscles usually does it for me. A sucking inward flex seems more effective than a pushing one. A dull thud indicates that the cup is open. Of course cup twirling works, too! Also, not pushing the cup as far in before letting go of the fold helps too. Let the cup pop open, and then adjust position.
3) For the punching down, I find it easiest to hold the cup sideways in the non-dominant hand, in the space between thumb and forefinger, facing out.
P.S. Props to those who discovered this fold independently (see comments below)!