Nathaniel Mendez-Laing opened the scoring fired and Posh doubled their lead thanks to a glorious Grant McCann strike after 65 minutes.
George Boyd guided in a third before former Daggers ace Craig Mackail-Smith and David Ball sealed the rout.
Still held aloft a replica shirt bearing the words `Proud to be a Dagger' as his side received a standing ovation from more than 1,000 travelling fans after the game.
Still said: "The shirt sums it up really - I'm proud to be a Dagger, proud of the supporters and really proud of the players.
"They have given me the maximum in every single game, week after week, and I could not have asked for more than that. Our rise over the last few seasons has been incredible and we always knew there would come a point where we would hit the buffers."
Source: PA
Source: PA