Wheyyyy you need to get yourself out of this friendzone crap. Can be done, but depending of how much a 'friend' she sees you, the more longer of a change in perception of you will take.
However, if this was ME in such a situation, girls usually ask if I'd like to join them, to which I'd comment on something sexual in some way shape of form.
You just have to gradually drill into them, that you are a sexual 'threat'. I like to make sure girls are aware that our connection is one of a sexual nature. If coming from a friend zone position, you will have to show her that you are a sexual guy before she believes this is anything more than her friend having pervy desire for her.
Showing her you're a sexual guy can be a veryyyy fine line between making her aware you're a very sexual guy, and sounding like 'hey women like me,

i pwomise, they do

'
So yeah. You DO have to be prepared to take risks though if you ever want to win anygirl.
Do you ever break rapport with her?