"....he saw them quite clearly in their little sitting room, the tall, black-haired man in his glasses, making puffs of coloured smoke erupt from his wand for the amusement of the small black-haired boy in his blue pyjamas."
-- Lord Voldemort in Godric's Hollow (DH17)
A charm to make coloured smoke rings emerge from the tip of one’s wand.
References from the canon
After inspecting Cedric Diggory's wand before the start of the Triwizard Tournament, Mr Ollivander causes it to emit silver smoke rings (GF18).
Harry Potter is linked to Lord Voldemort's memories while he remembers the previous time he had gone to James and Lily Potter's home in order to kill baby Harry. One of the memories is James entertaining Harry with coloured smoke rings (DH17).
While stuck in the past after the destruction of the Experimental Time Turner, Albus Potter also observed his father Harry as a baby laughing at his father's smoke rings (CC4.15).
Commentary
Notes
A similar effect may have been used to enchant the Dissimulator, a "musical" instrument introduced at the 1974 Quidditch World Cup, which featured loud cries of fan support and gave off puffs of smoke in the national team colours (Pm).
From the Web
About the Harry Potter and the Cursed Child play: http://www.harrypottertheplay.com
Pottermore:
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Tags: colors/colours entertainment family laughing showy smoke rings