Billy Vunipola has revealed that England have been told to stop being "too nice" by head coach Eddie Jones.
Jones takes charge of his first match in Saturday's RBS 6 Nations opener against Scotland at Murrayfield and has ordered his forwards to rediscover the belligerence lost under the previous regime.
Vunipola, who will start the Calcutta Cup clash at number eight, admits England's pack have been too passive in recent times and are ready to bristle once again.
"For Eddie we have been too nice. In the past we have been a bit lax and now we have to find our motivation and reason to bring the devil," Vunipola said.
"It's about not taking a backward step if we have lost a scrum or something like that because those little incidents in a game that can pass you by.
"If we lose a scrum and the opponents push us back then he wants us to have the attitude that 'next time you come around I'm going to smash you'.
"It's an intensity thing and you need that inside you and have to let it come out."
England have spent 10 days in camp under Jones and have so far been spared the 5am starts endured by Japan's squad, with the wise-cracking former Brave Blossoms coach yet to demonstrate his unforgiving side.
Jones is known as a ferocious taskmaster but so far Vunipola has only seen his 'good cop' persona as he enjoys the determination and obedience of players eager to impress their new boss.
"The boys are always on their toes because you never know what is around the corner," Vunipola said.
"It's like in football where you get a change of manager. At Chelsea, Jose Mourinho went out and a new guy comes in.
"Anyone could have walked in through those doors and everyone would have changed and been happy.
"It's a change of regime and you want to impress the boss and be on best behaviour. That is the place where we are at now.
"Hopefully we can keep it going for as long as possible because I have heard a few stories about Eddie Jones - the other side of him.
"We have only seen the good cop so far and I like the good cop a lot. It's like the teacher at school you have always liked and you don't want to get them angry.
"That is the same situation and you know you don't want to get to the point where you are apologising to Eddie Jones. By then it would be too late."
Vunipola will be picked in a back row also including Chris Robshaw and James Haskell when Jones his starting XV on Thursday lunchtime.
Danny Care will get the nod at scrum-half ahead of Ben Youngs, and Joe Marler is expected to be preferred to Mako Vunipola at loosehead prop.