Planting a song in someone's head so that they start singing, humming or whistling it. Derived from the character (James) Cobb from the movie Inception, whose job was to plant a thought into someone's head. Song cobbing (the act of planting a song) may take time as the unsuspecting victim may not start singing the song until minutes or hours later. Song Cobb is not to be confused with ear worm.
Now I got the "Facts of Life" theme song stuck in my head after hereing Gilbert singing it in the bathroom. He 'Song Cobbed' me!