Have you ever heard anyone use the phrase to "dog-ear a Thesaurus?" In the sports page today it said, "Indeed, the Bulls could have made fans dog-ear a Thesaurus with how poorly they played in the first half." I don't even know what they mean. Would it mean the fans were bored? But why a Thesaurus? I am capitalizing the word because they did, but I also don't think it should be capitalized.

I've never come across the expression, but surely it means that the fans ran out of ways to describe how bad they were, so ransacked a thesaurus to find more?

What Arnie wrote.

Makes sense.