A man or woman might do it to silently say:
“I like you.”

“I’m interested.”

“Remember me.”

It’s intimate without being overt — a private moment disguised as a formal greeting.

Often done with the thumb or index finger in a soft, upward stroke.

🌶️ Fun fact: In some flirtation guides, this is taught as a way to create a memorable, sensual first impression.

2. A Secret Code or Recognition Signal 🤫

Historically, secret societies, fraternities, and military units have used variations of the handshake to identify members.

The palm scratch could be part of a coded handshake, signaling shared membership or allegiance.