to undertake a dangerous or hazardous operation or activity—UK, 1867, as ‘to tickle the dragon’s nose’—‘to tickle the dragon’s tail’ was used of a nuclear experiment at Los Alamos during WWII
literally (1618): a blanket dampened with water so as to extinguish a fire—figuratively (1775): a person or thing that has a subduing or inhibiting effect
to use a lot of swearwords—first used in 1713 by Joseph Addison—alludes to the fact that troopers (i.e., soldiers of low rank in the cavalry) had a reputation for coarse language and behaviour
a person or thing that is insignificant or contemptible—1910—originally (1900): a type of small high-velocity shell, with reference to the high-pitched sound of its discharge and flight
every contribution towards a goal is valuable, regardless of how small it may be—UK, 1707—in Britain, particularly associated with Tesco, which has used this phrase as its slogan since 1993
various meanings, in particular: something with a larger capacity than its outward appearance suggests—UK, 1968—the name, in TV series Doctor Who, of a time machine outwardly resembling a police telephone box, yet inwardly much larger
the game of cricket played in the incorrect manner or improper spirit—hence, more generally, something contrary to traditional standards of fairness or rectitude—UK, 19th century
an oppressive, very confined or crowded space—UK, 1764—refers to the punishment cell at Fort William, Calcutta, in which, in 1756, the Nawab of Bengal reputedly confined British and Anglo-Indian prisoners
UK, 1941—a fighter pilot in the Royal Air Force; also used by the military land forces of any member of the R.A.F.—originally referred to WWII advertisements for Brylcreem hair cream, featuring a fighter pilot