Tengu are humanoid creatures with many avian features, including wings and beaks. Now, this is a problem when it comes to disguises.
Disguises in this setting work by covering one's body in utility fog, which can accurately mimic just about any common material, as far as shape, texture and feel goes.
The problem with utility fogs is that they're additive, and so, you can't subtract from a collision mesh (the object), only add to it (disguises are also called container meshes for this reason). This is especially painful for a tengu who tries to make a human disguise, since if they're found out, well, humans don't tend to be kind towards tengu kind.
So, how could a tengu's human disguise hide away the beaks and wings without exposing any of the collision mesh while also minimizing the risk of failing when closely observed?
The setting is feudal japan, tengu are flesh and blood, not yokai, there's no other magic or anachronistic tech besides these utility fog "container meshes".