Example 1: "John couldn't stop crowing about his new car. He kept showing it off to everyone he met."
Example 2: "She was so proud of her children's achievements. She would crow about them to all of her friends."
The origin of the phrase "to crow about" is thought to come from the behavior of roosters, which are known for crowing loudly to announce their presence or to attract mates. The comparison between human boasting and the crowing of roosters suggests a certain level of self-importance or overconfidence.