The lies I tell my children: why it's bad to fart?

I have always found an interesting way to respond to some of my children’s ... lets say "questions". You know, they ask you "Dad, why can't I play with matches"? And your stuck trying to figure out how to answer it with out going to the usual response: "Cause I said so"....

I have to admit, with my daughter, I tried my best to answer her questions, to give the why, the how, the reason why I say what i say. But after six years of why, why, why, why, why ... I figure I would do the opposite with my son. Sure, I use the tried and true response - Because I said so. But I also try to bring a funny twist to my response. It doesn't always work and sometimes it it is pure inspiration that comes to me like the one I shared with my son who asked me why was it wrong to fart in public......

Let me know what you use and what you think.