Before revealing the trick, let's see why it works. A recent study found that most straight women are attracted to other women. In other words, there is almost a better than even chance that your friend is attracted to other girls, at least somewhat.
Secondly, women are the biggest consumers of lesbian porn. Women are much more likely than men to watch lesbian porn. That means that there is a strong possibility that your friend has watched some lesbian porn and even if she hasn't, there is a good chance that she would like it if she did.
By now, you can probably see where this is going. The trick is to invite your friend over. Get on the internet, and eventually click on some lesbian porn and watch it together. If videos seem a bit much at first, just look at photos, such as from the NSFW verson of my blog Women Loving Women. Just ask whether she thinks a particular girl is hot or not.
Obviously, it won't be hard to tell if she likes lesbian porn and is turned on by it. If she does, keep watching and add some "innocent" touching. If you're old enough, a glass or two of wine can lower any remaining inhibitions,, although after watching lesbian porn for awhile, no alcohol may be required even for the shyest girls.
My book Lesbian Sex Secrets: How to Have Amazing Sex With Another Woman aims to help bi-curious, bisexual, and lesbian women take their sex lives to another level. To give your lover the best sex she’s ever had, starting tonight, click here!