I want to describe my own sense of humor :-)
I recently sent my friend's mother a thank you note for hosting me. She replied by saying that thank you notes are very important, and my note was very appreciated.
I responded by saying that thank you notes are indeed very important, and I've been trying to teach her son this for a long time. For example, I continued, I recently lent her son my sleeping bag and (as of yet) have received neither the sleeping bag nor a thank you note!
We are all very close, which is why I am able to rib her son in front of his mother like that.
But I want to be able to describe this sense of humor. Could my comment ribbing her son be described as 'cheeky'? I can think of no other word to describe it really. My intention was just to make fun of him in an amusing way... all the more amusing because it's a letter to his mother.
Oh, and the irony here is, it was her own son that reminded me to send a thank you note.