This illustrates how sometimes we think we can get away with sin.
Start by purchasing the gag chewing gum that shocks anyone who tries to pull the false stick of gum out of the package. You can find this gag at most novelty shops or even at a convenience store. Then purchase several packs of actual chewing gum that has packaging that resembles your gag gum.
The “set up” is to offer gum to about ten or so kids in the front of your class, you tell them the catch is if they choose to take your gum they must take every piece you offer them. Pass out as many pieces of gum as you like as you explain the allure of sin. You can use the deception of Eve in the garden of Eden as your text.
During your lesson secretly switch to the gag gum and offer it to one of the kids who accepted the terms of the catch. He/She will be shocked! Then offer the gag gum to the others who will most likely refuse to accept. Remind them of the agreement they made to take every piece if they took the first piece. At this point say the gum symbolizes sin in our life and sin always has a price. Point out all have sinned, but we don’t have to pay the price because Christ payed it for us. End the lesson with whatever is appropriate i.e. invitation, prayer or discussion.