I personally think you should have taught the young lad every swear word you could think of. (I know, Glasgow to Edinburgh isn't that far). Make it a game. Have the youngster repeat each word, then have him teach the dinosaur.

Tell him that the cool dinosaurs always said "Roarfuckshitassroar" and that only the weak dinosaurs just said roar.

Then with a wink and a nod, tell junior to make sure he tells his mother that GrandDad taught him these words.