pull the string
verb phrase - To pitch a change-of-pace ball, a very slow ball after the motion for a fast one (1937+ Baseball)
- To rudely reveal the truth, previously kept hidden; unveil true intentions; reveal the catch •The full form is pull the string of the shower bath: They doubled their efforts, showering her with affection, then they pulled the string (1928+)
[perhaps fr the use of a string to fasten and release a concealing sheet on something about to be unveiled; perhaps fr pull the lanyard, ''to fire a cannon'']