waggly

From waggle +‎ -y.

waggly (comparative wagglier, superlative waggliest)

1. Frequently waggling.
   • 1952, Bob Merrill, (How Much Is) That Doggie in the Window?:

     How much is that doggie in the window?
     The one with the waggly tail
     How much is that doggie in the window?
     I do hope that doggie's for sale.