Tuilagi passed his test last Wednesday with no minor faults, an achievement that not only surprised him but also the driving instructor who had feared the worst.
The 18-stone England centre is a powerful, hard-running player who tends to use opposing defenders as speed bumps rather than obstacles to avoid.
"My instructor was surprised because he thought I would be a really aggressive driver," said Tuilagi, who faces Australia for the first time in Saturday's Test at Twickenham.
"I am driving my brother's Dodge and when I passed my test loads of people were saying 'Stay off the road,' but I am a chilled-out driver.
"It was an amazing feeling to get my licence. When my test was finished, the assessor said 'Congratulations you have passed' and I punched the air.
"Then I started shaking his hand and I was holding his hand for ages. The best thing was he said 'You've got no minors, perfect driving'."
Tuilagi celebrated receiving his licence with the same glee that greeted the two tries he scored for England against Fiji three days later.
"For me, scoring a try is the best feeling ever as you can see from the massive smile on my face," he said.
On Saturday, Tuilagi will wear his favoured 13 jersey against the Wallabies and England will look to release the human juggernaut into Australia's midfield.
There are signs that Tuilagi's distribution is improving although it is a much slower process than his mastery of the Highway Code.
The England management are working hard to improve that side of Tuilagi's game, with a view to a potential international future at inside centre alongside Jonathan Joseph.
Not that Tuilagi wants to play there and be encumbered by the playmaking responsibilities that go with wearing the number 12 jersey.
"I am always clear what position I want to play in and that is 13," said Tuilagi, who spent his schoolboy days on the wing.
"That is where I want to be. If I get picked at 12 I will play there but it is different. You do a lot more distribution and I always work on that.
"But there is a lot more space playing at 13 and you get a lot more ball as well.
"My first game at 13 was against Sale; my brother Andy was playing 12 and Mathew Tait was playing 13 opposite me.
"I remember I scored two tries in that game and got man of the match, it wasn't too bad for a first game at 13!
"I got whacked a few times (from Andy). I remember I went through and I handed my brother off. The second time I got a whack in the face and my mouth was bleeding.
"It was good fun."
Still only 21, Tuilagi's approach to rugby is uncomplicated but the experiences of his first year in the international arena have taught him a lot.
Tuilagi was fast-tracked into the World Cup squad and one of the few players who actually made things happen for England at that tournament.
His decision to dive off a ferry into Auckland harbour was immature, but Tuilagi believes he has learned quickly from those experiences on and off the pitch.
"I have matured a lot as a person and as a player. The more you play, the more you learn in rugby and in life. The older you get, the wiser you get," Tuilagi said.
England as a team are young and inexperienced. Australia will boast more than twice as many caps on Saturday and veteran captain Nathan Sharpe has more caps on his own than the whole England pack.
But Tuilagi's relaxed exterior should not be mistaken for complacency.
"I never look at myself as being young because that is not an excuse on the pitch," he said.
"No excuses. People think when you have had a bad game 'Oh, he is young,' but if you weren't good enough you wouldn't be put on that pitch."
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