well, I had a request to see the individual layers so I slapped this together. I used three layers for the slobber as seen in this submission http://www.furaffinity.net/view/1615192/ (which is a detail of a drawing I'm working on). I use GIMP so it'll be different for you're program of choice.

The top picture shows all three layer combined. The one to the right of it is the base saliva layer. I simply slather some white squiggles using something like a %50 opacity round brush. Too bad I didn't save it but the brush strokes were fairly random that mainly looked like distorted 'W's and 'V's. It's then I take my favorite smear tool and smudge to living bejevous out of it. Smear smear smear until it looks ok.

After getting the base color down, I work on the highlights. This is different what I normally do as I usually do the shadows next. But the fluid effects works better the other way around.

I made another layer on top of it and set it to 'lighten only'. I then paint with a smaller brush with an opacity of over 90%. I hit it with the smear brush to to soften some of it and go back painting more of the 'glint'.

Now I do the shadows. I create a layer below the base color layer and set it to 'multiply'. With a brush with a dark color, I go over the bottom and to the side edges of the drops. You can be sloppy here as well cause (you guess it) I use the smear tool to reshape it till it's just a thin line under the beads. You may notice the shadows look thick is the isolated view I have here. Since the base color layer is on top of it (and set to normal), only a thin part shows.

Now when I work on this, I had all the layer visible. Otherwise you wouldn't be able to line them up. I also turned on the other layers of the drawing I'm working on. So it looks weird by it self but I hope you can get the idea of what I did better this way.

Feel free to ask if you have any questions. I won't bite... much.

P.S. I almost forgot. I turned the base color layer opacity down to about 50%. Don't forget to play with the layer properties to see what kind of effects you can get.