Tell him he's not allowed to use the words "And" or "But". Everytime he feels the need, put in a period instead. It's a little extreme, makes for a choppy story in some cases but if he does it a few times, he'll understand. It worked for my DS6 and he's a hardheaded little cuss!

Shari
Mom to DS 10, DS 11, DS 13
Ability doesn't make us, Choices do!