Dont add Silver Fulminate packed like directly dont add POP-ITs, you need to add the crystals in the bottom or the POP-IT material in the bottom and then add Potassium Nitrate on top. Pack or close the small bag or packet. Now you have a small pocket-sized smoke grenade like the one ninjas use.
A perfectly working smoke grenade
To make it work just throw the bomb on the ground and when the bomb strikes the ground the Silver fulminate explodes first thus creating heat that also causes a reaction or combustion of the Potassium nitrate and sugar mixture thus causing it to burn and create instant smoke.