I'm very open about it, and will mention it anytime the context of the conversation indicates a necessity. This is especially true when people try to attribute anything (success, good fortune, narrow escapes, etc.) whether their own or mine, to a deity. It's the perfect example to point out the uselessness and hypocrisy of magical thinking.

As soon as they ask what my tattoo means or they mention they're whatever they are.

Whenever it comes up, I guess. Usually it's not something I bring up out of context...

As soon as I can … as ultimately, the closeness of our relationship depends on the base agreement that religion is a hindrance to human advancement.. Till then, it’s arm's length