The Corkman said: "Coaching the Barbarians is a unique honour and it gives me the opportunity to work with some hugely talented people. It's very different to coaching Six Nations or international level.
"You just have to act as a conduit between these players - a kind of facilitator. In many way with the Barbarians less is more."
O'Sullivan has been involved in the IRFU Review of Ireland's World Cup performance, presenting his report to the IRFU Appointments Committee, and admitted that "the process has nearly come to an end."
"For Ireland the World Cup was hugely disappointing. We failed to produce anything that vaguely resembled our form during the season," he said.
"Since then it has been a tough time trawling through everything that happened. The Barbarians offers me an opportunity to get back on the horse.
"It feels good to be back on the horse. You always ask hard questions and the hardest questions you ask are of yourself."
With Ireland's 2008 Six Nations opener against Italy now barely two months away, the onus will be on the Irish team to rekindle the form which saw them claim three Triple Crowns in four years and beat some of the Southern Hemisphere's top sides.
O'Sullivan added: "One thing with Ireland is you can't afford to be complacent. I don't see there being a huge number of changes in the personnel. We certainly have something to prove in the Six Nations."