(A longer version of this column originally appeared on Real Money, our premium site for active traders. Click here to get great columns like this from Jim Cramer and other writers even earlier in the trading day.)

I wrote a few ago that I'm somewhat surprised that my mother hasn't asked about Dow 20,000 yet, but I suspect it won't be on her radar until it leads the evening news.

As I wrote at the time:

"My mother makes such a great contrary indicator because she simply repeats what the 'guy on the radio' says. Once she's heard something enough times, she feels compelled to ask me about it.

For new readers, know that my mother is one of the best contrary indicators out there. Her last pearls of wisdom came two weeks before the election, when she asked if she should sell before the election because 'they' say ('they' being 'the guy on the radio') that the market will go down if Trump wins the election.

So, if my mother should call and inquire about Dow 20,000 and tell me how 'they' say it's bullish or something like that, we'll know it's time to sell. If she's excited enough to mention it in a conversation, we'll know that sentiment has really gone too far."

When I first wrote about my mom and Dow 20,000 back in December, the market was coming off of a terrific run and we had just touched an intermediate-term overbought reading. So, I expected a period of market choppiness -- and that's exactly what we got. Just look at all of the recent sideways action.

But now we're further along and there's even more giddiness in the market. So, if my mother finally calls me to ask about Dow 20,000, it will surely be a sell signal.