play along

English

play along (third-person singular simple present plays along, present participle playing along, simple past and past participle played along)

Used other than figuratively or idiomatically: see play,‎ along.
The children spent the day playing along the river.
(idiomatic) To take part in a charade, deception, or practical joke.
James thought it was cruel for the fraternity members to make the pledge think his father had died suddenly and refused to play along.

James played along with their cruel trick.
- 29 February 2012, Aidan Foster-Carter, BBC News North Korea: The denuclearisation dance resumes[1]
  North Korea loves to spring surprises. More unusual is for its US foe to play along.
(idiomatic) To participate in a joke or trick while hiding one's knowledge of its true nature.
I knew that my blind date was an April Fools trick, but I played along anyway.
(idiomatic) To play a musical instrument in synchrony with a playback of a recording.
I like to practise guitar by playing along with records.
(idiomatic, US) To cooperate or go along with a plan.
I have doubts about your plan, but I'll play along for now.
(idiomatic, US) To pretend to cooperate or go along with a plan.
I haven't told him yet, I'm still playing along with his scheme.
(idiomatic, UK) To manipulate (someone).
The con man plays his victims along until he senses the moment to ask for money.

hide one's knowledge of a joke