They learned pretty early on that Blaine didn’t exactly have a high alcohol tolerance. Sure there were the couple of times in high school when Blaine got drunk, but they didn’t think much of it, Puck was the one mixing drinks at Rachel’s party after all, and they had just assumed that Sebastian had swapped Blaine’s empty drinks for full ones at Scandals.

Years later, when Kurt and Blaine had their small apartment in New York they tested what they already thought a little more thoroughly, and surely enough, when Kurt was only starting to feel a pleasant buzz from the drinks, Blaine was already thoroughly tipsy.