A lot of the money shots are faked.
Ever see Margarita Mix? That is commonly used as a substitute.
A friend of mine runs a porno site which deals exclusively with Chicks Getting Facials. For "effect", and for the proper "shot", at the right time they route a small tube with Margarita Mix in it, and blow it all over her face. If done well, they can even use that tube, and the proper camera angle, so that it *appears* to be coming out of the guy.