O'Driscoll posted a photo of his retirement meal: a takeaway pizza, a can of Coca Cola, and a massive toblerone.
The rugby legend is relaxing, after expressing disappointment on having to leave the field eight minutes into his final game of professional rugby.
O'Driscoll's 186th and final appearance for Leinster did not go to plan from a personal perspective - he was forced off with a suspected calf injury in the ninth minute - but he was delighted to join fellow retiree Cullen in lifting the trophy afterwards.
O'Driscoll, celebrating his fourth league success after Leinster's 34-12 victory over Glasgow, told RTE: "I've always said you can't plan anything in this game. What happens happens and you've got to roll with the punches.
"It wasn't going to be a good day for me today, only getting eight minutes or whatever but (winning) is what it's all about."
Asked what he will miss most from the game, he replied: "Hanging out with all your buddies and having a laugh, coming in every day and making sure that you're well equipped with your abuse because you know there is some coming at you!
"I'll miss that and the support that we've had. It's been a two-way relationship."
This morning he tweeted this message with a picture of him with fellow retiree Leo Cullen: "Not the way I'd hoped to play it out but s**t happens! Been one of the great pleasures playing with this man! #leader."