Once upon a time, yawning was a neutral action. However, for most of my life, I can remember that I would occasionally let out a big yawn and at the end of it would be a burp. That's why I hate yawning in public, because I don't know when the next yawn I take is going to have a burp at the end of it.
In other news, I think my clock is ticking...and not my alarm clock. I don't like it one bit.