Why Hugging a T-Rex is Not Funny

I wrote a joke on the whiteboard in the residence hall a while back: "Reminder: Sunday is hug a T-rex day!"

Nono and Qing walked in and saw the board. They discussed it together in Mandarin, but eventually the conversation flowed over to me:

Qing: What is a trex?

Me: It is a big dinosaur.

Qing: A dinesor? What is?

Me: With motions. You know, raaaarrrr!

Nono: Oh! She tells Qing in Mandarin what I'm talking about.

Qing: Less confused for a moment, then re-confused. Why should we hug it?

Me: Suddenly at a loss. Because, probably nobody ever hugs them.

Qing: It's dangerous.