Is this someone who is on her period, or just gave birth? Or is it just randomly happening to her? New birth control?
If your loosing a lot of blood AND feeling weak or dizzy then you should go to the ER but have someone else drive you
is the blood coming from your pee or your vag like you are on your period?
It is common if you are on your period and you are sitting or laying for the blood to "pool" in the back of your vag then when you stand more will come out at once.