Softcup usage question?

So I recently started using the softcup. And, even though the plastic part unfolds to hold the period, I was wondering if it really does extend in the body? Because it always seems to stay flat when I take it out, therefore not lasting long, spotting in my underwear. Maybe I am putting it in wrong? Does anyone else have this problem? Do reusable menstrual cups not have this problem because they are lower? So I guess my main question is why does the softcup not hold very much because it is not unfolding?