I first cut off about ¾ inch of that coffee stirring straw and super glued it inside the bottom nozzle of the rocket. Don’t get a lot of glue on the engine; keep it on the straw and nozzle.
Then I carefully squeezed the engine igniter through the straw until it stopped. You might have to straighten out the leads on the igniter with the pliers. Just don’t let them cross, because they’ll cause the igniter to malfunction.
I finally rolled up a piece of the recovery wadding and wedged it in the straw between the leads. This holds the igniter in place and keeps the leads from crossing.
(Don’t worry about clogging the nozzle. The igniter, straw, and wadding will burn up really fast.)