1 cup(with holes already that you want to make bigger)
2(or 4, if you have them available) piercing needles. Any gauge will do, but I recommend 14 or 12. I used both. Keep in mind that the gauge determines how much edge you have that is sharp enough to cut with, but the bigger the gauge, the flatter the edge will be.
NOTE: Please be VERY CAREFUL with the needles! Not only are they very sharp, but they cut VERY EASILY and will make you bleed(as I found... oops) if you accidentally poke yourself with one. ALSO, make sure that you dispose of them in a sharps container. NEEDLES ARE DANGEROUS, especially since these are hollow, and sharp, and can really do harm if stepped on or something.
What I did was to take the needle and poke it through under the hole and try to cut up into it. This proved to be somewhat ineffective in removing the inside of the hole, but I then used the needle to basically carve out the inside of the hole. It worked pretty well, though better with two needles. What I ended up doing for the most part was, after the initial carving, sticking a second needle through the hole, blunt end first, and cutting the excess that it pushed out away with the other needle. Basically, just using the sharpest parts of the needles as mini knives, and preforming intense Diva Cup cosmetic surgery.
I did have a few slip-ups. The first hole was rather nice, especially since it was my first shot. I tried to replicate it, but it didn't work quite as planned, so that hole was a bit sloppy. By the third hole, the needle was relatively blunt, and so it was very difficult. I ended up slipping, and slicing maybe 1/4 of the way through the inside rim of the cup. It still works, still functions, and there isn't really any problem that I can see arising from this. After this, I switched to a 12 G needle instead, and it worked very nicely. The larger hole was easier to work with, and it also gave more sharp surface area so that there was more to cut with. The size of the needle doesn't determine the size of the hole, just how much area you have to cut with. Regardless, I wouldn't go any larger than a 12 G, being as a 10 G is much larger than a 12, or a 14, which is equivalent to the size of the holes of the Lunette.
The results? A cup with slightly less suction. Its much more functional now, I feel better wearing it, and I'm super excited as well. Tomorrow I may try again and make the holes slightly bigger again, or maybe add one or two instead. I'll keep this updated, definitely. Hope this helps someone!