Billy Vunipola says England must stop buckling under pressure but denied they are mentally weak after falling short in the Six Nations.
Coach Eddie Jones plans to recruit an expert to work on the players' mentality after England squandered a 31-point lead to draw 38-38 with Scotland in their final match of the tournament.
England were also in front against Wales before Warren Gatland's men came roaring back en route to winning the Grand Slam.
Jones feels his players have been suffering psychologically since England's Rugby World Cup failure on home soil four years ago, but Vunipola says they just need to be more resolute when under the cosh.
The number eight told Omnisport: "I wouldn't say [mental] weakness [is an issue], I'd probably say something that we haven't, as a group, haven't experienced before [is] being under that pressure.
"A lot of us are probably new to it and it's a good learning curve for us and hopefully we can take the learning from it and stay positive because the last thing we want to do is feel sorry for ourselves.
"We've got to pick ourselves up, play well for our clubs and put ourselves in the best position to play for England again."
Vunipola thinks there were plenty of plus points for England to take after they finished second.
"I'm disappointed we didn’t win the whole thing. We did a lot of good things, we did a lot of positive things within the tournament." he added.
"We're probably five or 10 per cent off where we need to be and that's huge going into a World Cup, we've still got things to improve on and hopefully we can do that."
- Vunipola was speaking at a coaching session he was leading with fellow Saracens and Harlequins players on behalf of Land Rover at Beaconsfield RFC