Yes. You'll need
- some "Crepe Hair" (which comes in a braid) - get 3 colors, your target color and a shade above and below that color.
- a fine toothed comb
- a sharp pair of small scissors
- SPIRIT GUM
- A Hair Drier with temperature settings (burning your actor's face is a bad idea)
With the braids in one hand, you'll be combing through them one at a time, First 2 pulls on the main color, then 1 pull on each of the other shades, repeat until you have a nice clump built up in the comb.
Squeeze the trailing edge of the hair sticking out of the comb between the inside parts of your extended index and middle fingers, use the scissors to cut as close to the comb as possible... hold onto the hair you've cut with your fingers just like you had it before you cut.
Spirit gum the subject's face where the tuft of hair is going to go (you'll be working up from the bottom and out from the middle to get the hair to overlap correctly).
Use the hair drier to get the spirit gum TACKY, then press the cut ends of the tuft onto the gum vertically. Use the hair drier again to set the Spirit Gum firmly.
Repeat to build out the main shape of the facial hair you'd like to have.
Once this is complete, run the hair drier over the whole thing for a while until all the gum is set.
Using the scissors and a beard trimmer, shape the mustache/beard the way you'd like it to look, just like you would a real full mustache/beard.
I had to learn this on my feature when my main actor shaved for an interview! The resulting footage is close enough that you can't tell at a glance he's wearing a prosthetic beard.
Please post any results so we can see them