I have never seen my pet use his may cast fuel spell. He has used his may cast unicorn though. I have tried triggering it by placing traps and attacking a target, but he never uses it. Does anyone know how to trigger fuel?
i don't know how but i'm guessing it's by luck. Like the way my fraken bunny has may cast healing current and it casts it even when i'm in full health.
It's extremely rare. I had a may cast windstorm babydactyl for ages, and NEVER ONCE saw it use its little spell.
These may be the extremes though, because they involve multiple blades or multiple targets.
My fire friend has a phoenix with mc fire trap and spritely. He has had the same first generation phoenix ever since the pet quest, and has only seen it cast a trap twice. Once in a mob battle in Drum Jungle, and again while we were doing xibalba. That probably comprises thousands of individual battles with this pet equipped, not doing anything except sprite. And he is not a passive player, he blades and spams and heals and feints. (He has like 70 outgoing :P )
So if you aren't seeing it, it's through no fault of yours. It's just a really, truly, low-incidence talent.