Cash register head

There is a lady that Marti and I have come to like very much, who I think was quite the skeptic when she first came to see us in a group.  This lady had a son who had died.  The son has spoken to her on numerous occasions since the first time she attended a group.  One of the things he told me on that first visit, was that his mother had a nickname for him, that had something to do with money.  He told me it was unusual and that I probably wouldn't get it.
I said to his mother, "your son says you have this name you call him,  I'm not sure what it is, whether it's dollar or dime or something else, but it has to do with money."  Well she sat there saying nothing and I repeated what I just said, adding another monetary word or two, still no response until her friend sitting next to her made her speak up.
"Well I used to call him cash register head."  She said.
To which entire room full of people, erupted in laughter.
Shaking my head, looked at her and said.  "Did you expect me to say Cash register head?  Your son already told me it would be hard for me to get."
Later on another occasion this lady came to see us privately, and the first thing her son did when he showed up, was to hold the Ace of spades card for me to see.  I told her this.  To which she responded by saying.
"Oh my god!...you just blow my mind."  She didn't say what the card meant.
"Good I'm glad."  I responded with a chuckle.
Then a few minutes later her son made me feel a tattoo on my left forearm. I told her this as I traced the outline of it.
She gave me a look of disbelief.  "That's where he has the Ace of spades tattooed on his arm!"  She said.
I came to like her a lot.  It made me happy for her to know that her son was visiting her, but as with so many people that come to see us, I thought she was being a bit difficult with me when I first met her.