I use the basic
clear medical tape from Walgreens or Wal-Mart. But definitely before make up, and on a dry surface. Also, I place tape on the cheek bone so that I can really squeeze the performers head. You can provide a good deal of pressure without hurting them. I then do a piece high and behind the ear where I can push into their skull, and then the
wire goes to their neck where I can put a third piece on their spine. Some actors (Especially the sweaty ones) specifically come to me instead of my crew because they know it won't come loose during the show.
The key is to not be gentle, but not be a jerk about it. Above all, talk to the actors so they know what you are doing to them. In many ways, they are people too.
I work at the high school / middle school
level, so I don't mess around with hair mics unless the actor is wearing a wig and even then, only if they project enough to get picked up. I find that the
wire will come loose from the pins and be super obvious by show's end. I'd rather just tape the mic to their
face and be done with it. 16 visible, but functioning microphones are far less distracting than one
wire sticking up off the back of an actor's head.
I had a director/ actor once confront me to say that she had never been told to get her mic Before make up and that we shouldn't require that for her cast. Conversation went something like this.
Me: As a performer, do you ever have a problem with your
microphone coming loose during a performance?
Her: Yeah, occasionally.
Me: Well..... I don't.
End conversation,
call times adjusted accordingly.