Tava is a gaseous intoxicant favoured among the kinds of people who favour such things in the Chiss Ascendancy. It is cheap and easily available in the Ascendancy, with mild doses caused inebriation and higher ones temporarily knocking out those affected.
While Tava is quick to take effect, it wears off just as quickly, with few effects remaining once the the quantity of it in the air is exhausted. For this reason, it is much-used by young Chiss students for pranks on each other, and on their more boring instructors.