One good way to help them resist is to rehearse proper reactions to these situations ahead of time. Rehearsal or role playing is essential. No orchestra performs in public unless they rehearse frequently before a performance. Fire departments rehearse rescues in buildings designed to simulate truly dangerous situations. Police are trained to react appropriately to crowds chanting offensive slogans.
Astronauts rehearse their mission many times before liftoff.
Young people practice driving a car on the practice range before taking to the streets. It's only natural that you and your youngster should rehearse proper reactions to and proper thinking about the exposure of enticing situations. Each argument attempts to evaluate an action by determining whether the consequences are desirable or not. These philosophical variations of ethical relativism are treated separately in other pages at this site. You should read and be familiar with the arguments of each of these philosophies.