I also hate to say it like Jen but Abbey did that when she was really little and I mean little. She hasn't done it for a couple years so not sure why. Her obedience trainer when she was a puppy said it was because cavs are such babies. Me since finding out that she has sm I have thought of it as her second symptom--the first being a seizure 2 weeks after we got her. I'd also be watching her but at least you are aware of sm unlike I knew nothing of it. Hopefully its just like jato said.
Linda, Georgia, USA
Winston--shih tzu-male, Darby female tri, Bentley male blenheim and Chelsea, black-tan
Abbey my beloved tri who is so embedded in my heart--RIP Sweet Princess