You have a really good cake on the table. You ask if anybody would like a piece of cake.
Pick someone, tell them to come up to the front and put on the apron (it is a messy cake).
Then, grab a piece of cake with your hands, and throw it at the unsuspecting victim.
Ask the rest of the class if they would like a piece of cake. (hopefully they'll be too afraid to say yes)
Then clean up quickly, and delicately hand them and the rest of the class, the nicely presented piece of cake. Explain that teaching the Gospel, is like giving people cake.
The Gospel is inherently good, just like the cake. However if you "throw" scriptures and history at them, they are less likely to accept it.