Couple different ways to do it. Rubbing the tips of you fingers on an alum block can help a lot as it pretty much drys lather out as soon as it touches it.

What I do when doing my cheeks is start pulling up in my hair. Then as I clear a section of lather i bring my hand down stretch repeat.

When I do my neck I pull down around my collarbone and lift my head way up and away from the side I am going to shave.

In the mustache and mouth area it's pretty much facial contortion.

Pretty much those techniques keep my hands out of the lather.

I also use the heel of my palm for a better grip sometimes.