How did Mr.Bennet tease Mrs. Bennet when Mr. Bingley moved to the area?

Mrs. Bennet scoffs at the idea of Mrs. Long introducing the Bennet girls to the new gentleman, then she exclaims "Oh, forget Mr. Bingley". Then Mr. Bennet says he already asked Bingley to meet his daughters. Mrs. Bennet thinks she is being teased.