Some people can be so nasty, they tend to tease about things they have no idea whatsoever. Unfortunately for males as they are developing, there hormone levels are totally off-balance which means you have more of one hormone and not enough of the other.
Being teased because you have man boobs is a difficult period especially if you are a teenager who does not know why they have developed them. I think the most important research you should do is to find out why you have man boobs then you are able to explain it to people and hopefully they will have a better understanding and stop making fun of you. The other thing to do is to find out little tricks that will be able to hide your man boobs when you are out with your friends so you don't get teased.
Visit your local doctor, medical clinic or even research it on the internet as to why you have developed man boobs, and the ways you are able to get rid of them, you may find that it is not as bad as you think. Also discuss this problem with your closest friends and you might find that they have a similar problem and did not want to talk about it. You will all probably laugh about it because your friends were trying to hide their problem too.
As a young adult you will most likely notice that your man breasts will slowly disappear anyway and as said earlier they are sometimes produced because of a hormonal imbalance, the more research you do on the problem, the more you will find it is not as bad as it may seem which will therefore strengthen you emotionally to handle all the teasing. Don't forget the saying...."Sticks and Stones may break my bones and words will never hurt me".