I still can't believe anyone would watch porn of a model with a baby's throwup and drool all over her face.
Obviously OT. I'm not sure if you're being decorous but it's not throwup and drool, but semen. Unappealing stuff like this always has the same basic origin: A ritualized performance of sexual shame and/or guilt expressed simultaneously as sexual desire. I suppose the semen is supposed to be degrading and the degradation of the model projects the shame of sexual desire onto the Other. Those of us who neither feel semen to be degrading (sticky, yes) nor degradation of the Other to be satisfying would probably not enjoy what's-zis porn. (Already forgot the spelling. Probably unconscious resistance to an unpleasant idea!
As unpleasant as it is, it doesn't seem to actually harm anyone any more than any other type of strangled sexuality.