The semi-sick, semi-high feeling you get when taking NyQuil as a sick person during winter just to stay semi-coherant. This feeling may make you believe you feel 10x better than you actually are and allow you to get in a full day's work, a load of laundry done, and several home repairs finished before falling into a bone- weary heap on your bed.
Betty: "Aren't you going to go home sick? You looked awful yesterday."
Jean: "Nope - I'm on a NyQuil High - I'm not going home until 6pm!"
Semester finals were coming up and was sick as a dog, so I got on a NyQuil High and studied all night long.