For me, it's about drawing someone out or seeing what they're made of (tasty cookie? or nasty prune?)
Kidding about is my way of playing. I'm trying to get you to play with me. There's no ulterior motive other than to have a good time and to make a new friend. I like to see people relaxed and laughing and enjoying themselves. When I met a good ISFJ friend for the first time, I kidded him about his coveralls, which were tree camo. I kept saying, "Where's X? I thought X was here! All I see is this walking tree!" He came into class the next day in his NIN shirt and wearing an earring, like "SEE?! All better now?!" We both started giggling, and became friends.
Teasing can take two directions, one good, one bad.
Good teasing is when I like someone and after having gotten to know them, I like them even more, and I want to provoke a few unbidden responses from him. It's like playing, but far more serious and with romantic tones. I want to see how he responds to my closer approach. It's chemistry.
Bad teasing is when I'm trying to purposely run someone I don't like or trust into the ground. I hardly ever employ that. It's not laudable.