The movement of the cup in the canal shows that it hasn't created a seal with the walls of the vagina. Usually, the cup is supposed to be positioned at the base of the vagina, but it is highly dependent on the user's anatomy. Try using a different fold and reinsert. Make sure that the cup opens up fully too. Also make sure you are using the right cup size. Check your size here. Watch this video to understand how to use the cup.