Check cajun on keys to the vip (it's on youtube) where he asks a girl whether he looks like a drug dealer. Listen to his voice tonality and observe his standing position. If showing desinterest is your goal, this is the way it's done.
Teasing girls is easy, just say what you think and remain calm as they may/will counterattack. People can only hurt you when you accept what they're saying to you.
Example:
I once teased a girl having an iphone. Couple weeks later I got one myself. She saying to me: "you've got your own iphone with you and you were teasing me with mine!" and I was like "Yeah, you're so right." in a calm tone. And that was it
