A few hours ago I went over to my uncles house and his mother-in-law was there making some tamales (we're Mexican). My other uncle was there and his 5 month old baby girl was there with him. I don't see my new baby cousin much so I thought I'd spend a few minutes playing with her. I played with her and before I left my uncle's mother-in-law, with a serious face, told me to draw a cross on my baby cousin's forehead with my own saliva because I could "harm" her and won't let her sleep. I kind of looked at the lady like, "I'm sorry did you just seriously say that to me?" I am not kidding, she was being completely serious. I just started slowly walking off and she stopped me and told me to do it. OF COURSE I refused and told her I don't believe in her stupid ideas and she just looked at me in disbelief. I have to deal with a super religious aunt who won't leave me alone and to this day I don't know how to tell her I'm an Atheist but now I also have to deal with this crazy lady?!
If you were me, what would have done? What would you have said to her? I'm still surprised she seriously sad that to me.
You can inform her how much bacteria is in the saliva. Sounds like your aunt wants to harm this baby for some odd reason. I can't think of any other reason, but I think it's understandable why she would want to since religious people love to harm others.
I would have told her to snip off a hunk of her hair, nail it on the North side of an Oak tree at midnight. Then all of her troubles would fade away. Couldn't hurt:)