Imagine in a group of people who you feel shy to be too friendly with, something makes you laugh too much in the manner that you cannot control your laughter and it makes you feel shy, however you cannot avoid laughing loudly. How can one apologize at the time of laughing and what can one say in such a moment?
I'm sorry; It made me laugh badly; I cannot stop my laughing.
I guess the above sentence would sound idiomatic in this sense, but I have no idea of it's being natural.