Anyone have this issue?

HisBetterHalf

DD just holds her pee.  She's not really having many accidents but that is because she's just not going.  She'll do the pee pee dance and tense herself up so that she doesn't go.  I still have her sit on the potty frequently but she won't let it come out.  I know she has to go because of the way she is dancing around but she's just not letting it come out.  Could it be possible that she's mastered holding her bladder but doesn't yet know how to release it?  Its making me really nervous.  She will wet her diaper during nap and at night but won't pee on the potty and has only had a few accidents in her underwear.