I have two cats, both under 6 months old (I guess you could call them kittens). I have used a spray bottle in the past as negative reinforcement, which worked great on one of them (the one that's scared of water) and less effectively on the other (which, for some reason really likes water).
Lately, this has proven to be less effective. The latter cat (water lover) is no longer responding to this bad reinforcement and doesn't seem to be fazed by the mist of water.
Can I add something to the water, without it being harmful to the cat, that will make it more uncomfortable for him and maybe react to the use of the bottle in the way I expect him to? (Maybe a tinge of lemon juice for sting?)