This is difficult to use an object lesson because you don’t want to hurt or cause discomfort to anyone. But maybe a little discomfort is okay?
Find some annoying sound (used to be able to do fingers down a chalkboard but how many chalkboards are out there?) like a balloon being rubbed or static from the radio. Something that will cause most class members to lose focus on the teacher and concentrate on the annoying sound. As this is happening, tell a short story. At the end, quiz the class on details and see how many paid attention to the story and how many focused on the annoyance.
The point of this is to demonstrate when we focus on our physical comforts it is difficult to pay attention to other matters. Not talking about needs because that’s a whole other matter. But when we are in pursuit of physical pleasure our spiritual self may wane. However, when we focus on our spiritual self we can find pleasure within the bounds the Lord has set.
Giving Our Spirits Control over Our Bodies by President M. Russell Ballard