Pinching this itchy muscle

The story:

Well, the entire song is really hard to understand in general, since the lead singer sings in her native accent. But every time I'd sing it, I'd belt out "Pinching this itchy muscle" because it was my favorite line, and I thought it was so random, then I'd just kind of mumble the rest of the song. One day, my mom and I were listening to her Cocteau Twins CD and I sang this, and she gave me such a weird look then told me to look up the lyrics.