Menstrual cup advice

Hello ladies I am after some advice please about using cups. I have used on for a few cycles now and think it is brilliant but found towards the end of my last period that it was difficult to get the cup to unfold in me properly and form a seal. I have just started my period today and having the same problem. I wriggle it around push it in further and pull it back out even try to use my fingers to get it to pop out but nothing works. Really don’t want to go back to tampons so would appreciate any advice. I have even looked at online videos to try folding it another way but no joy.