Sounds like baby teething to me.. I used a firm "NO" while substituting a teething bone. The no spoken in a slightly different elevated voice would get their attention, but you must be consistent for them to learn. Good luck..
"There’s no changing people, and we can’t even help people with whom we’re emotionally involved. Let them be, stop expecting things from people who cannot provide those things, and recognize that we can live happy, productive lives regardless of what others, even close relatives, are doing or saying."