Wow, Chick
I didn't know it was so complicated
I must be in my second year using the moon cup and I just pop it in, give the stem a tug to make sure its in far enough and away I go...

I have never thought about fit around my cervix - I assume it is "normal" as I have had 7 pregnancies and 5 live births and I assume some doctor or midwife might've said something

The only time I have "leakage" issues is during 36 hours or so when it is very heavy and if I don't change every hour... well, its messy.

So maybe it anchors itself by luck?