The 29-year-old joined the Black Cats from Wigan in a £1million deal in the summer.
“You can now see a different player who has matured,” he told the Northern Echo.
“You can see that in his career so far. But the thing with Titus is you cannot keep telling him how well he has done.
“You just have to keep hitting him with a big stick, get after him to concentrate.
“That’s how you get the best out of him.”