The cup should sit however it is comfortable as long as it is inserted correctly just under or around the cervix.
Make sure to aim the folded cup down and back towards your tailbone and not straight up.
#5 – How to Insert & Remove a Menstrual Cup
Most users insert the cup completely including the stem. The stem can be trimmed to your preference but make sure that it is still easy to reach. Don’t trim the whole stem at first. Only trim bit by bit until the desired length. How to Trim the Stem
There are some users who leave the stem long and let it hang down, but most don’t find that very comfortable.
My perfect cup is one that is easy to use and can’t be felt at all while I’m wearing it.
Good Luck! <3
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