That will work, and I have done it a few times as I work for a mobile fone operator and sometimes get 2 pin plugs on things.. but I certainly wouldnt recommend it as a permanent solution, or for a child to be doing it.. the best type of item to use for his is the top of a biro pen...
If it has an american plug on it then an adapter will be fine, best/cheapest place will be somewhere like asda, woolies etc.. its a 2 pin adapter, the sort you would use to charge an electric toothbrush, not a european adapter that you would take on holiday as these convert a 3 pin into a 2 pin not vice versa.
HTH!!