Well, I now have two ideas:
1.They will be totally scripted, at certain parts in, say, a boss fight or other major skirmish.
OR
2.A battle command accessible using the "Taunt" Command Materia. Similar to the way Marle's "Provoke" attack sometimes caused a status effect, the effects of taunting can be done the same way, with about half (or significantly less) the MP cost of the equivalent spell. Of course, there's also the humor factor.
The possible exception to this is the concept that Shinra, Inc. had in mind for Cait Sith: Dual Moonings. That's gotta be scripted, it'd probably get major laughs from the player! If we're gonna do that, then here's the next big decision:
Textured or
Gouruad-Shaded? I think I just said too much...