Rogue: Help! The gibbering mouther's got me!
Psion: Hang on, I'll distract it...
Rogue: *gets free and runs* Phew! Thanks a lot... what did you do to it, anyway? It just started sort of trembling and making squelchy--
Psion: I don't want to talk about it.
Fighter: Ack! Rust monster!
Even if you envision manifesting euphoria on an animal as being just like scratching its tummy, doing the same to an aberration is still kinda weird.
Anyway, this may just be me. As usual, a very cool idea with intriguing complexities.