In the short-lived Strike Force Five podcast (five late-night talk show hosts during the writer's strike), one of them talks about this. They mentioned how they

In the short-lived Strike Force Five podcast (five late-night talk show hosts during the writer's strike), one of them talks about this. They mentioned how they tried and tried but couldn't get the garlic to actually do that. When they got a chance to interview Scorsese about it, his response was "I made it up" :)