Yuumi as teammate

I fail to see why it would matter if shes on you or not? What situation would you want her to not mount on you?

I'm at a loss as to why it wasn't considered to add that as an option to begin with. Mixing player error with player error isn't just casting the skill at the improper time, it's just a bad time in general. I've yet to play her, but the idea that I commit to putting either myself, my teammate, or both of us at risk due that skill sounds like too much of a pain to deal with. Save committing to jump arcs to Castlevania, please.