What I did was I inserted the cup as usual, then grabbed the base of the cup (not the stem!) and pressed on the sides ever so slightly to unseal the cup rim from the vaginal walls. I then turn my wrist in a circular motion so as to turn the cup, repeating this several times until the cup has turned 360 degrees, and what do you know, it works! The cup becomes rounder and seals better, I don't have to stick a finger up my vagina to ensure a seal, and I'm good to go!
Note that if there isn't much blood coating the vaginal walls when you do this, it might hurt a little, since there can be some friction when you turn the cup.
Let me know if this works for you!
