Need wordpress tweak to allow sliding text in a column

I'm running the X Theme Pro on Wordpress ([login to view URL]) and am using the child theme that I would like tweaked. On many pages I plan to have rows that contain two columns. One column will contain several stacked images so that that column will be fairly long and the column next to it will be primarily empty except for a small block of text. As the user scrolls down the page, when they come to this two-column row I would like the small block of text to stay at the top of the screen until they get to the bottom of the row, and then it can proceed off the page. You can see an example of exactly what I'm talking about here: [login to view URL] Scroll down until you can see the headline "Gatorade" and as you keep scrolling down, the text will slide with you. That's the effect I'm looking for. My theme has a child theme that can be edited so that it doesn't get overwritten during theme updates. When I create the small text block, I can easily add an ID or class to the text. (see attached screenshot) I want it setup so that whenever I enter an ID or class or (not sure which it should be), it will have the properties I'm looking for. This way, I can easily replicate this in future Wordpress posts or pages by adding the ID or class to any text block. When the screen is scaled down for smaller devices, the two columns currently just become stacked on top of one another, in which case the effect is no longer necessary. I would like it to remain this way. Please let me know if you have any questions. Please review the link I posted above as it will show you exactly what I'm looking for.