Is sucking your teeth after emax crowns harmful?

Creating a suction movement with your tongue is not likely to harm the crowns in any way. When the crowns were placed, they were permanently bonded with cement. 
I am glad you like the fit of your new crowns! That is great. It sounds like you are getting adjusted to having these crowns in your mouth, which can take some time because the texture and shape are different than what was in your mouth before. Within a week or two, you should be used to them.