We people try a lot of stuff to make children obey. That includes the Santa thing and J’esus will punish you’ etc, like in the above comic.
But, please don’t make them panic by giving a wrong view about Jesus. Don’t make Jesus look as if He is the one waiting to punish the boy if he does something wrong. The whole thing may cause a negative image of Christ to develop in his mind.
Do it the other way. When he does something really bad, tell him “Oh! So you are not with Jesus, You like Satan more? Hey! Look…. Jesus is just crying seeing what you did just now…” and stuff like that.
Make them love Christ, and don’t make them hate Him.