When you are mentioning something you did, something you are wearing, etc. to make someone else give you a compliment for it.
The following are examples of "To Fish for a Compliment":
Her: Oh, I'm so tired of baking. These cinnamon rolls took me all day to make.
Him: And they sure do taste wonderful!
Her: I guess I fished for that compliment.
One girl to her friend: I was so lucky to get this sweater on sale last Thursday.
The friend: It looks great on you!
Husband: Man, I'm tired of changing tires on all our cars.
Wife: Thank you so much for doing it. I really appreciate it.
When you give a compliment, quickly followed by a rationalization of the circumstances, which takes away all the joy of the compliment.
Origins of how "to pull a Mr. Fox"; from The Fantastic Mr. Fox by Roald Dahl -
Mr. Fox to Ms. Fox: "By the way, you look unbelievably beautiful tonight. You're practically glowing." He then looks up and around him. "Maybe it's the lighting."