Alicornutopia

The first place my brain went was "secondhand smoke???"

Neh. Doesn't work right in my head.

Laughing gas I made myself? It has effects on the body and cannot in principle be returned, and to me at least it seems properly aesthetic.

Would it be different if it were a gas with nutritional content or I somehow laid claim to all the oxygen in the area?

Nah. Pollenclouds are an unusual case and I think humans by and large do not have things that count. Windflower poisoning somebody, maybe.

If the fairy uses a hookah/bong in which is being smoked plants that I grew myself?

Sugar bullets?

Obvious things like "the concept of smoking" are not going to be what gets an exception out of me here.

Sugar bullets can work.

Is it just that inhalation requires an especially strong claim of ownership, like how a berrybush owns their own berries much more strongly then they own plants they just happen to have grown themselves, or is it a different issue? In other words, would it be useful to think of an inhalation-based vassalization as always requiring the same sorts of things as a food vassalization between fairies?

That would probably help yeah.

Am I correct that being hand fed by one’s master or vassal is always safe and this is not just an approximation? I am in particular thinking of a vassal going to a third-party berrybush fairy and feeding their master the berries in the hope of escaping.

If this is actually safe, it suddenly becomes a lot more attractive to trade for candied dewdrops from untrusted leaflets and berrybushes.