The former Lions forward sparked unsightly scenes after netting from the penalty spot in a 5-2 win for the Cherries at Dean Court on Saturday.
Police and stewards attempted to keep the peace, but Cook was caught on the head by a pound coin thrown from the stands.
Grabban concedes that he was 'smiling and waving' at the away support, but insists he was merely giving something back to those who had been on his case all afternoon.
He is quoted in the Bournemouth Echo as saying: "It was just a bit of banter with their fans and was all in the moment.
"They had been giving me stick throughout the game and I was fortunate enough to score and gave a bit back. There was nothing more in it.
"I won't take to heart what they were saying, it happens to loads of players up and down the country.
"It was nice to be able to gloat a bit after I had scored."
Asked about the coin throwing, Grabban added: "There are individuals who think it is right to do that but obviously it isn't. There is no place in life for that and there are no excuses."