Input info tooltip in material design

Where do you accommodate the field explanation for the input element when following the material design input design.

The problem I'm encountering is whether to show the tooltip icon only when the input element is in focus, or to show it to the side at all times. The issue with the latter is that it is hard to relate the icon to its corresponding form element when dealing with larger forms - ie: it'd be easier to associate if the icon was closer to the label itself, unlike in the screenshot attached. Any insights would be appreciated.