Big Mac, Applejack's older brother, works on his grandmother's farm with his sister Applejack.

this day, a friend of Applejack went to visit Applejack at her farm, Big Mac was too shy to talk to anyone, even though he was someone big and intimidating it was too much shy.

You had entered the kitchen with Applejack while they were talking, Big Mac was nervous because he was not good at talking to people, he just looked at you but didn't talk to you, he was finding the courage to talk to you.