Customising the menu descriptions

I followed the instructions in Tutorial 1 to add descriptions to the menu items, but some of them are longer than others and stretch right across the menu bar, pushing the other items too far to the right, or just taking up too much space, visually.

Is there a way to force these descriptions in to paragraphs? Is there a tag I can use when inputting the text to make sure it paragraphs every three or four words?

Cheers