LOL. . .ok, lesson time. Sit up straight and pay attention. Here's how each works:

The Instead (available at Walmart) looks like one of those jelly bracelets all the kids are wearing - you know the ones that say "Livestrong" and stuff like that? Well, around the bottom of the "bracelet" part is a thing membrane. You squish it together, one sdie to the other, and insert it, stopping when it reaches your cervix. Let go, it'll pop open, against the vaginal walls, thus catching the fluid. When it's time to extract, you hook it with your fingertip, slide it slowly out, and dump it in the toliet. Wrap it in some tissue and discard.

The Luna's and Diva's are similar in theory. No strings, no cotton. Nothing that can harbor the growth of bacteria. Think, trombone mouthpiece? Goes in the same way, is smaller than the Instead, but works with natural (safe) suction against your cervix. Blood exits the uterus, through the cervix, and into the Luna/Diva. There is a stem on the bottom of those, sometimes you need to trim it. It does not extend past the vaginal opening. You cannot have sex with the Luna/Diva b/c of the stem, which is why I use Instead if I'm feeling particularly amarous.

I'll try to find some links and bring them back and post. You can look at them, check them out. If you are considering such a change, I'd suggest purchasing a box of Instead (about $6.00) and trying them first. They are different than the Luna/Diva, but the theory is the same. I find my periods to be MUCH more sanitary this way, and I'm not in constant fear of anything leaking. I've yet to have a leak with the cup.