I'm bisexual and very attracted to my best friend. We hang out a few times a week and text daily. She knows I'm bi and that I am attracted to her, when we hang out I often pull her legs into my lap and/ or hold her hands. I know she doesn't like people touching her, but she never resists or gets annoyed when I do this. I am too chicken to try more because she is a really important part of my life and I don't want to make her angry or uncomfortable. How do I get into a romantic relationship with her? I don't want to loose her as a friend but I want more from her and its driving me crazy.

You just need to have the conversation with her. She might be curious but doesn't know how to tell you

She knows you are bi. She knows you are attracted to her. What else is there? I don't know why you expect strangers online to be able to tell you 'how to get into a romantic' relationship with someone who already knows of your desire.

No, you don't 'do' anything. Yes, she will be uncomfortable. Stop touching her; you are just frustrating yourself. She may wonder why you have stopped, and you should tell her why, but be very careful how you say it. She may want to end the friendship for your sake, since you can't seem to handle it. If you truly mean it when you say you don't want to lose her, then curb your sexual desire.