Simple plugin: show pop-up text on hover

hi, I am finishing to work on a wordpress site, and would need to add pop-up texts on some expressions (the expression is the title and link of a webpage; the pop-up text is a short presentation of that page). Actually, as I will have to apply these different pop-up texts to many expressions, I would need an easy way to do it. Important: - the pop up text might have italics and bold characters (this format should remain) - this hover effect shouldn't affect format of the main text - this hover effect should work on tablets and phones (on first click) (you can find 2 examples of what I want, attached) thanks