I use smoke on TBHs for colonies that are agitated/easily annoyed. But for colonies in a good mood/warm days or when feeding I use a water spray.

Water only. I tried sugar but water is more effective: if you spray sugar solution the bees want to stop to collect it: if you spray water, the bees run away. Ideal when closing bars on a TBH where the risk is of crushing bees.

A spray is more convenient as well (although I light smokers using a two flame mini blowlamp which takes 30secs with dead wood.)