Hasn't that happened to most people? If not, you haven't lived long enough. Believe me, if this is the most embarrassing thing that you do or happens to you in the course of your life you are doing really well. I'm old and have been laughed at more times than I can remember. He who smelt it, dealt it!
Announce it! Oh yes!! I farted!!! And laugh with them. Its human nature. Why be shy about it when everybody in the world does it. The only reason people laugh is because it makes a funny sound most of the time. Just think yolo! Be like, yeah I farted. So what? :)