San Francisco - the song:

My back was killing me, and I heard about this Thai massage place that was supposed to be great and… cheap. I went in with my pal Robin Eaton, who was in town to do some writing with me.

When we walked in, the man at the front desk somehow thought we were an item, so he put us in the couples room. We were singing and giggling, trying to distract from the slightly uncomfortable fact that we had never seen each other totally nude.

Our two Thai masseuses came in, saw our silliness, and started singing themselves. One of them launched into a very broken-English version of the old Scott McKenzie song "If You Go To San Francisco." It was pretty cute. Robin asked her if she had actually been to San Francisco, and she answered in a sad, whispery tone, "Oh, we can't go. They won't let us go."

Robin and I looked at each other -- what kind of place was this? I had just read an article about how thousands of Asian women and girls are kidnapped, tricked or sold into prostitution and smuggled into the United States each year. So, I couldn't help wondering.

When Robin and I got home, we worried, got all serious, and wrote this song.

Oh, and I went been back to that place a couple of months ago. I was curious, but more importantly my sciatica was acting up. Prisoner whores or not, that walking-on-the-back trick worked. And I also came away pretty convinced that the parlor is legit, especially since I saw one of the masseuses get into her brand new Prius -- not usually the car of a sex slave. But, what do I know?

On the video, check out the legendary drummer Jim Keltner, the same guy who drummed on Lennon's Imagine album.