Sparkly decoration (6)
'sparkly decoration' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tinsel that I've seen before include "Christmas tree decoration" , "Christmas foil" , "Enlist the glittering decoration" , "Cheap shiny stuff" , "superficially attractive" .)
(Other definitions for sequin that I've seen before include "that sparkles" , "Small circular spangle for ornamenting clothing" , "small ornamental circle" , "Shiny decoration for clothes" , "Small shiny disc on a garment" .)