tickles the dragon's tail

Verb

tickle the dragon's tail (third-person singular simple present tickles the dragon's tail, present participle tickling the dragon's tail, simple past and past participle tickled the dragon's tail)

1. (idiomatic) To do something that has a risk of going catastrophically wrong.
   • Climbing so close to an erupting volcano was tickling the dragon's tail.
2. (idiomatic) To annoy an irritable person.
   • Don't tell him the headline's misprinted; you don't want to tickle the dragon's tail.
3. (nuclear physics) To bring two subcritical masses close together in order to find the edge of criticality.
   • The laboratory head tickles the dragon's tail whenever we have guests as a show of machismo.