I honestly would never do this but that is just me personally. I was a very similar situation as OP( taught swim lessons to 5-12 year olds meeting weekly from once a week to 5 times a week) and I just ignored it and it went away. Kids want attention from you and there peers, if you dont give it too they dont get entertained and stop. I also am 17 so I find the idea of parenting someone elses kid inappropriate and not helpful. Maybe also its just me but I dont really consider stuttering a disability. I guess it is but I never really considered myself disabled and maybe I am view disabilities differently.