This means: If you did that on my birthday you would see a physical demonstration of an angry and upset person. 'Hissy' comes from the word hysterical and means having uncontrollable emotions. Usually associated with women. You should laugh when you hear this sentence it's meant to be funny.

Update yourself! How I Met Your Mother is the new Friends. I'm guessing that's Phoebe's quote? Nevermind, it's Chandler's (which is weird because guys don't have "hissy fits" :P) Chandler is saying that if someone did that on his birthday, he would be very angry/upset/go crazy. A "hissy fit" is what an angry cat can have. If you have a cat, and it's not happy, you would know what Chandler means here.