My dd tugs, plays and covers her ears quite a lot. Sometimes she will do it when she is overtired/getting ready to sleep, and very often when she is having her bottle she will put her hands over them both and play with them. She has been so vigorous tugging and playing with them at times that she has made them bleed.
They don't appear to be causing any pain, and my dh believes it is a comfort thing.
Does anybody elses dc do this? Is it a comfort thing? Or could she be indicating a problem? I've been reluctant to go to the gp as my dh does not believe it is a problem and she does not appear to be in pain.