Hmmm that might be it. I think he gets a little over enthusiastic with regards to play too!
This'll make you laugh. Last night I was lying on the sofa with a blanket over me watching the telly, when Tachi came and sat on the arm of the chair by my head. On seeing this Akamaru ran and pounced on the sofa, then on my face and then chased after Tachi. The problem is when he pounced on me, he put his paw straight into my right eye. As my hands were under the blanket I was too slow to stop him. lol. It was like a slow motion thing, I could see a paw coming towards me, but it was too late to do anything about it. Maybe I shouldn't moan about the nibbling!