Female Dog

Question
I have a female Pekingese that is not spayed and sometimes when she licks herself she starts doing the jaw chattering thing. I've seen male dogs do this when a female is in heat but never seen a female do it to herself before. Is this an indication that she's coming into heat or could it be something else? I've never experienced this with my larger females and this is my first time owning a small breed dog. Not sure if there's much difference when it comes to heat cycles (large breed vs small breed).

Any info would be greatly appreciated. Thanks!

Answer
Kayla,
My experience has been that they do not like the taste of the urine.  The males are attracted by the blood, but they don't like the urine taste. The females are cleaning themselves but if they get the taste of the urine they chatter.  At least my dogs do this even when they eat something particular strong tasting or sour.
Nancy