I am going to give you the benefit of the doubt that you are indeed being honest here, because TFP is based on honesty . . .
Not personally into scat or that sorta thing . . . but i see nothing wrong with people exploring things they wish to in their own sex lives . . .
Yes, i have heard there are serious health concerns . . .
I would veto the mouth area, you don't want to go there man . . . too much issue with bacteria . . .
If she Really want to try scat . . . why not let her do it somewhere else . . . like on your chest for instance??