I'm definitely not going to give you pointers on how to score with your friend. But all I've got to say it generally ladies don't like sleeping with their friends. But um, Good luck?
Why are you asking the women? You think they really know what needs to be done? There the followers not the instigators. You've set a difficult task for yourself but it is possible. Whether or not you can pull a 180 I don't know.
You need to create an attraction. The problem with your situation is you've skipped the attraction stage and have gone straight into the rapport stage. Attraction is about tension and flirting and sexual danger, while rapport is about sameness, connection, and loosening tension. Friends (which are what you are) have rapport.
I'm basically going to take quotations directly from bobairs blog entry titled "How To Seduce Her From “Friend” To “Lover”. You can find more detail here… link
Playfully tease her about things she’s confident in (if she knows she has a great body, then tease her about how unattractive you find her… just remember that this only works well if she knows you’re teasing her, and if she is truly confident about herself. Don’t tease an insecure model about being fat, because you’ll ruin the poor girl.)
Role-play with her, while always assuming she’s making sexual innuendos. This is about being fun, while also helping her to associate you with sexual banter.
Say “No” to everything she says, suggests, or asks. This is a simple way to break rapport.
Only give her one compliment. If you’re secretly into her then you’re likely giving her way too many compliments…. Especially when she’s looking for them. Instead open your evening with, “Hey, you actually look pretty good tonight” almost like you’re being sarcastic. But then drop it like it’s hot.
Lead by being assertive. Don’t ask for her permission to do or say things. Don’t waste her time with “Well, what do YOU want to eat?” Instead make suggestions, “Let’s go to that new place downtown, I hear they have great Chinese food. I’ll pick you up at 6.”
If she responds well to the above tactics you need to escalate your relationship. Take things in baby steps and if your lucky you can brake your rapport and create attraction. Once she’s attracted to you the possibilities are endless.
Will your wife give her approval?
You can ask. She'll probably say no; if she wanted to do you, she probably would have already.
It depends how long you've known this chick for. If it's for a while, you have practically no chance as you've been put into the friend zone. If not you can just ask her out on a date.