I suffered with this hun, I went to the drs (in the UK) about it and tried to describe it to them but didn't understand what I meant. But when I mentioned about having problems down below to the dr in Denmark, she was the one who said did it feel like whooshing air. I would hear noises when I was getting up off the bed and sometimes when walking. I hated it and thought others could hear it (but they couldn't)
She checked me over and she said I had a slight prolapse (I felt like that area was going to fall out iygwim) I also had an episiotomy which didn't heal properly and thats where I could feel the air escaping from. She said that I needed to be doing my pelvic floor exercises every day to help.
I definitely don't notice it as much now but it did take quite a few months. I found wearing maternity pads helped, so I carried on wearing them for a while after I'd stopped bleeding.