He's basically putting on a private doo-wop show for the seagulls. Then he stops, spreads out his arms, and adds in the harmony: In the still of the ni-i-i-ight!
In this scene from I Funny: A Middle School Story by James Patterson, a humorous moment occurs where a character appears to be performing music just for the seagulls. The description highlights the playful situation, suggesting that the character is entertaining the birds as if they are an audience for a private show.
At the same time, the character pauses, stretches out his arms, and begins singing in harmony, adding a musical element to the scene. He sings the line, "In the still of the ni-i-i-ight," creating a vivid image of a lighthearted, whimsical moment that blends comedy with a touch of musical performance.
