I don't remember where I watched the interview of MSD, but this is what he said,
Reporter- What do you talk to other batsman between overs?
MSD- (First he laughed). Actually you will find it funny what we talk between overs. When we went to Bangladesh the food quality was not good. So me and Raina were playing and in middle of the overs we were talking about food. He said,"Dhoni bhai, yaha khana accha nhi h".
MSD said that they talk rubbish things when there is no pressure on batsman but if in a situation where they need to score under pressure they talk only about game plan.