I'd say that if you wanted to go this route, you'd have to set it up beforehand. That is, the magi in question, when the deal was being struck, would have to say "Right, you want my first porn. Got it." And then get the farie to say yes to that statement. Ie,
"Right, Frog protection."
"...I think we're on the same page."
Hm - Troupe's interpretation of farie bargains, in that case. In my previous troupe, faries are very much about the exact wording. If this occurred, the likely result would be a golf-clap, and a congratulatory "well played, sir." from the surrounding farie court. Of course, the farie would then attempt to do the exact same thing right back to you.
Or alternately...that's actually what they really wanted, and the magi just THOUGHT they got away with it. But for that kind of treachery, I'd recommend a pretty high-level fae (maybe not Mab, but one level down.) Or at least a farie specifically known for being clever in that sort of thing.
For example - Magi X was trying to get your magi's first-born child (for revenge, or an arcane connection, or whatnot), and bargained with the farie to get it. The farie didn't particularly want to do that, so they bargained with your magi for their first Bjorn, knowing that you would likely use the pronunciation loophole. Then, when you bring in your first Bjorner, the farie took the Bjorner to the Magi X.
Of course, the reason it does this is because the BJORNER had bargained with the farie to "allow me safe passage into Magi X's sanctum, so that I can wreak my vengeance on him for killing my paren." And the farie's requirement was "OK, but you'll have to do some odd stuff with this random magi first." Insert (possible) romantic relationship with your magi (or not, depending on how that plays out), but at the end it's all about playing three magi off each other using technicalities, in order to set up a triple-betrayal vengeance thing.
EDIT - the trick would be to get the Bjorner and your magi to NOT talk about what was going on - and having your magi try and seduce the Bjorner (in order to get out of the bargain), while at the same time having the Bjorner pretend to be seduced (in order to gain their vengeance) - where if they simply had been open and communicative about it, there would be significantly less drama. But because they DON'T, there's angst to go around.
And of course, a story for the Fae.