i've managed to figure out how to insert and remove my cup, but i have one question. my cup feels like it's going to pop out all the time even though i insert the cup including the short stem. am i doing something wrong or is it supposed to feel like this. when i check it, it's still in place. nothing sticks out so i'm wondering why it feels like it's falling out. please help.
(i don't want to clog this board with lots of posts, so this is my last question)