I like the way you think. I have an old video where this woman deep throats her partner, then a little ways in they start having her spew up milk she has recently swallowed. I mean a lot of it. It makes a stinking mess, but it is hot when I am in the mood. Here's a screen cap.
They may be heading in this direction, as they have been putting a lot of lube down 'em 'fore they gag 'em. Maybe a colored lube?
/insert Tritone joke/
I've enjoyed the Vomitorium on the Gag Factor pay site.
-Chuck, Vegetarian fanboy