The plot for this episode may be unintentionally based on the real-life 1969 romance novel hoax Naked Came the Stranger, which was deliberately poorly written by 24 coauthors in an attempt to make a commentary on the literary content of the top-selling books of their time. The average reader completely missed this point and the book became a top-seller itself.
When backstage, Brian says there are only grey M&Ms . Like in humans, colour blind doesn't mean seeing only in black & white, it means not being able to see certain colours. In dogs, the colours they don't see are greens and reds. Green will appear light/white and red will appear dark/black.