Enabling text tooltips for the variation swatches is very easy with the Smart Swatches Pro plugin. Follow the instructions below:

1) From your WordPress Dashboard Menu, navigate to the Products > Attributes and get into your desired variation Edit mode.

2) Select Tooltip Type > Text and click on Update. 

3) Go back to the Attributes and click on Configure terms to add tooltip text. 

4) Now, add your tooltip text for the product variations. 

The final outlook would be something like this: