Manipulating My Child

According to all his teachers, Cameron is a delight in class, helpful,
polite, SUPER positive and encouraging to his teachers...but HE'S
MESSY!!! His handwriting is sloppy. He does everything FAST (eats,
plays, writes, piano). He's been FLASH since a baby. When he was 3-4
years old, he broke something by accident nearly every day!!!

He doesn't seem to be able to consistently stay focused on the work, so
he often forgets details. He'll miss 77 on a grammar worksheet, but
will recite the rules to me perfectly when we're looking at it at home.

It's not an "on-purpose" kind of thing for him, and the check lists
don't motivate him. I've been trying to think HOW??? HOW??? HOW???
He is SO relational. His EQ is off the charts. So, This week i tried
this (felt a bit manipulative, but I got him where it hurts):

MOM: Cameron, looking at this paper, it looks like either you are not a
very bright boy, or else your teacher is not a good teacher.

CAM: WHAT??!!!???

MOM: You can tell me Cam, is Miss den Hartog not a very good teacher?

CAM: She's a GREAT teacher mom! She's the BEST!!!

MOM: I'll bet when Miss den Hartog sees your work it's pretty
discouraging to her. I'll bet she thinks that maybe she's not a very
good teacher if you can't do better work or write neater than this.

CAM: Really???!!?

MOM: Yes.

SILENCE.

MOM: That would be sad if Miss den Hartog was thinking she's a bad
teacher because of your sloppy work.

CAM: Can we not talk about this anymore?

MOM: Do you think you can try harder to complete your work neatly so
that you can show Miss den Hartog that she IS a good teacher?

CAM: Okay mom. I'll do that.