Explain what is T.J’s theory of getting out of work in Chapter 4?

From the text:

“See, fellows, there’s a system to getting out of work,” T.J. was expounding as I sat down. “Jus’ don’t be ’round when it’s got to be done. Only thing is, you can’t let your folks know that’s what you’re doin’. See, you should do like me. Like this mornin’ when Mama wanted to bring back them scissors she borrowed from Miz Logan, I ups and volunteers so she don’t have to make this long trip down here, she bein’ so busy and all. And naturally when I got here, y’all wanted me to stay awhile and talk to y’all, so what could I do? I couldn’t be impolite, could I? And by the time I finally convince y’all I gotta go, all the work’ll be done at home.” T.J. chuckled with satisfaction. “Yeah, you just have to use the old brain, that’s all.”