Under the spreading chestnut tree
[spread arms wide - tap chest - tap head - arms up high]

Where a wasp sat on my knee
[say 'zzzzzz' - tap knee]

I was happy as could be      
[say 'ha-ha']
   
Under the spreading chestnut tree
[arms wide - tap chest - tap head]

Next verse ... replace the word 'spreading' with the action only

etc. etc. with other verses with more and more of the actions and 'zzzzz' and 'ha-ha' only ..