Was joking only in the sense that it is not a common option available. Not joking in that it is by far the better option.
Serious answer to the packing problem.
Scents degrade and change in the shipping and storage process, so a model might not be delivering to the customer exactly what she intended. For the best quality delivery, I would pack in as much insulation as possible to protect from heat, with a desiccant pack to protect from moisture.
Vacuum sealing the package may not be the best option, as the air surrounding the panties may be removed.
I would recommend that the customer warm the panties by placing them on a hot pack until warmed to 37 Celsius, open, let humidity adjust, then enjoy.
In reality, so long as they arrive quite quickly, any standard packaging method will probably be sufficient. A scented envelope and letter would work for me.