Hmm… suggestions, eh? Lemme see here…. (hard to simply word this so here a tiny story to get the idea across…) Safety spoilered in case it was a bit too saucy for this rating.
Moondander: Well then, I guess my wish would be for Twilight Sparkle to spend more time with me whenever she can. Studying, practicing magic, learning new spells.. just whatever takes my fancy at the time I suppose.
Loona: So you want to make a slave of this Twilight-whatever then? That’s easy enough.
Moondancer: Wh-! Wait! That’s not what I meant at all!
Loona: Hmm… so more of a desire sensory effect then? Just able to do you how you want and when you want it?
Moondancer: I-… Sort of? I just want her to spend time with me doing things I like to do when I want her to.
Loona: Still easy enough to do then. magical effects start along with some incantations
Moondancer: realizing the wording on that last part -wait. You meant to say “doing the things I want” rather then “doing me how I want”, right?
Loona: finishes incantation and magics Sure, whatever. The trigger phrase for her will be “Let’s go, Twilight” whenever you are ready to get down to business with her. floats down and knocks Moondancer onto her back
Moondancer: Oof. That seems like a simple phra- mmh. Sudden 69 position action
Loona: Meh. Whatever, just finish fast so I can get back. still on phone proceeding with 69 actions stuffs
-somewhere in Ponyville some hours later-
*A friend, bystander, family member, etc. casually says the trigger phrase. Awkwardness and/or sexy times ensue depending on the feelings and desires of the phrase user at the time.*
Edited
I SAID CARNAL NOT CARAMEL!
She was too much of a wuss to sacrifice an actual live chicken. Hey, the chicken still died! It counts!
Edited