Hands above the table until the end of the post. This is a thought experiment to do with a christian.
1. Find a christian who admits to masturbating or look disbelievingly at one until they admit it.
2. Ask them to imagine "doing it" and then ask what their reaction would be if their mother, father, sister, brother or best friend (whomever they wouldn't want to do it with) walked in. Would they stop?
3. Ask them if they walked into a room where that person was if they would simply start masturbating in that person's presence.
4. Repeat as many times as you want to see the person blush and squirm.
5. Once you are done teasing them, ask them why, as a self-admitted masturbator, they can a) masturbate in front of god (who is omnipresent, omniscient, perfectly holy and worthy of all their obedience and adoration in their understanding) and b) cannot masturbate in front of a finite human being.
What quality does the human being possess that god does not that causes them to stop?
Voilà! Practical Atheism. Let them ponder that for a while instead of trying to convert you.