First of the month

My parents have this thing they do on the first of every month.  It's a game to see who can say "rabbit Rabbit RABBIT!" first.  My mom, who spent the past 4 months 2 time zones to the east, sometimes cheated by sending texts at midnight her time.

So, to you, Mom and Dad, I say:

rabbit

wabbit

rabbit

Have any of you heard of this?  Do you know where it comes from?  Do you do it?

Wikipedia says it's a British superstition.  It's strange that my family would do it because the most recent immigrants were 5 generations ago and not from the UK.