Is it normal to want to have sex with my bff

I'm straight and my best friend (girl) are really close we both have boyfriends and talk about sex and compare notes I told her one day I couldn't find my g spot and she said she'd help me find it..I've been curious ever since we flirt every now and then but nothing blatant like I wanna skrew you etc..I jokingly said I'd wake her up with some fun but think I secretly meant it and she said that would be fun lets do it..should I? Would it ruin our friendship?