Apple Watch band release button stuck

You can also cover the Watch and run hot water or the connector while pushing the button.

I recently had this issue with one side so I "gently" used the corner of the one band side to press/release. If this won't work contact  

You might try dabbing a swab in WD 40 and applying it to the release button. If that doesn't work make an appointment with the Apple store Genius Bar.