How can I make hover-text (tooltip) here?

[barking_iguana]

I remember someone once posted a trick, combining two tags that Live Journal supports, to make pop-up hover text appear in an entry. One tag to create the text and trigger and the other to give the proper appearance so that users know to or not to hover there, iirc. Maybe one of the tags was lj-specific, but my memory is even more vague on that point.