This is my first try with an Instead Softcup, and I can't get the rim past the pubic bone. The rim just keeps sliding towards the opening of my vagina. Has anyone else had this problem and solved it, or is it just too big for me? For size reference, I have a small Lunette and I have cut the stem off most of the way. It works well but insertion and removal is painful, so I thought I'd try Insteads, which can be narrower for insertion and removal. Thanks in advance!