Hey guys I’d like some thoughts on how to ask a girl out. I have absolutely no problem doing that, but I have one very touchy situation right here
Here it goes: The girl is a close friend’s sister… yep

. I cannot really ask her to hangout (just me and her, even though she would want to) because, why would I suddenly start to hangout with her without my friend? My friend would probably be like “why the fuck aren’t you asking ME to hangout?!

”. At the same time, I don’t want to spend time with her behind my friend’s back. Btw I live in an apartment by my own and she lives with her family.
I don’t really care if I get the girl or not; I just want to make sure that I don’t hurt my friendship with the guy by trying to spend time with his sister. I know that if this girl is interested, our friendship will never be the same, but as you know the real regrets in life are the risks you didn't take.
I just want to spend time with her, chill and see if there is potential for anything else.
How would you proceed?
Any ideas?