"We know what he can do on the field. For us, that's the easy part," he said of the player with whom he's been nicknamed half of the Bash Brothers.
"But what Baz brings is that confidence. You mightn't be the best skills bloke but you can bluff the opposition. He gives the blokes the confidence to play the ball not the bowler.
"You don't look down the wicket and see (big-hitting West Indian batting star) Chris Gayle. You look down and put a 50 cent piece and land it on that," he told the Tony Veitch radio show.
"He instills that confidence whether they've played five or 50 games, that you can win from any position. It's all about execution and it's unbelieveable how much he bluffs teams."
McCullum, who missed one game through suspension over a slow over rate from the Heat, has hit 277 runs at 46.16 in seven games, with a 170 strike rate.
Lynn also appeared to confirm longheld suspicions over the veracity of the bowling speed gun, which detects the pace at which fast bowlers are delivering the ball.
"It depends how much hype there is around the bowler. They might bump it up for the ratings.
We're talking about entertaining. They, say, put the radar up five or six kmph and you get more ratings because people are interested in talking about it," Lynn said.
And 26-year-old Lynn gave lie to the notion that playing test cricket for Australia is every players' dream.
Lynn, who has played one ODI and five T20s, maintains playing for his country isn't his priority.
"I'm not going to say yes or not to the baggy green (Australian cap). At the end of the day you have 15 years tops to maximise your career.
"If I get a baggy green great. If not, I've always said it's not the end of the world. There's more to life than playing cricket for Australia."