It's the one move that has every NRL referee on notice - but no-one fears getting Canterbury's prolific decoy play wrong more than Bulldogs back-rower Frank Pritchard.
'Frank the Tank' is the crucial middle man in the left edge move which has proved so pivotal to Canterbury's success this year.
His run is aimed at sucking in defenders and creating room for the likes of Josh Morris and Dally M player of the year Ben Barba to weave their magic.
It is a play which has caused much consternation for those in the video referee box - with rival coaches adamant Pritchard should be penalised for an obstruction.
Pritchard knows what he has to do to make it legal, and he won't want to get it wrong against South Sydney in Saturday night's preliminary final at ANZ Stadium.
"Dessie's (coach Des Hasler) got it down to a tee - if I miss the line or miss the jump he's going to blow up at me," Pritchard said.
"It's a must have, it's a must-do.
"We get our lines right, it keeps a smile on his face, otherwise I don't want to be on his bad side."
This week his job will be to get Rabbitohs pair Dave Taylor and Dylan Farrell interested enough to commit their defensive attention to him rather than Barba or Morris.
He admitted he put plenty of work into the move, under the watchful eye of Hasler.
"You have to, you have to sell the play, to get the players to bite on you," Pritchard said.
Asked if he thought players were deliberately running into him to attract a penalty, Pritchard said: "Yeah, they're trying to get a penalty.
"Me and Des discussed it he said I've just got to push through the line instead of holding up otherwise you get blokes who just fall over and milk the penalty."
Pritchard was part of an unchanged side named by Hasler on Tuesday, with Dene Halatau - who only recently returned from a knee injury - unable to force his way into the 17-man squad.
Hasler said he had used the week off to work on his side's discipline with ball in hand.
"We can't afford to give away that much possession (as they did against Manly) in this game given that Souths have got the best completion rate in the competition," Hasler said.
"We need to be mindful with the ball."
Asked if he had noticed an increase in tension within the squad leading into their first sudden-death clash, Hasler said:
"No, its all about winning - even the first final the carrot was to have the week off.
"They (the players) are pretty smart, they know what's at stake."