NOCAYB (acronym for "No One Cares About Your Boner") is shorthand reminders of one of the true maxims of a polite interaction online: nobody cares about your boner. Typically deployed in situations where a party has unnecessarily brought up the attractiveness of a celebrity, or sexualized something or someone to an uncomfortable extent, bringing an unfortunate halt to normal, non-perverted conversation.
Dude 1: "Yo, man, that Anne Hathaway is a great actress."
Dude 2: "Yes, she is! She also has really nice feet. I want her to crush my balls like wine grapes."
Dude 1: "...Um, NOCAYB (No One Cares About Your Boner), Dude 2."
When a man cares so much about someone who is going through something bad that they have an involuntary boner. It is not sexual, it is a natural bodily response to intense emotions.
When she told me her mom was diagnosed with cancer, I really hope she didn't feel my care boner when I hugged her
When you care so much you get hard
Damn Stacy, When Molly told us about what happened to Jim. I was so distraught I went home and had sex with my wife. I had one hell of a care boner!!!