It's rude to give away another person's things without permission.
Toby's friend forgets a movie a Toby's house and Toby's brother sees it and asks if he can have it.
Toby wants to answer his brother about whether they can have the movie.
Toby says that he'll have to ask his friend if they still want the movie before giving it away.
Toby says his brother can have the movie his friend left behind and gives it to them.
Toby's friend is glad that Toby didn't give their movie away without asking them first.
Toby's friend is upset that Toby gave away their movie without even asking them.