Don't stamp on your face or, even worse, your friends' faces. And, okay, this is actually a composite image. We took a picture of Emily (not her real name) and superimposed ink stamps on her forehead and face. No children were harmed in any way in the shooting of this picture. And, yes, we have the consent of her parents.
Karate Chop It
Simply hold the stamp with one or both hands and gently push the stamp down to make a clean and clear impression. Using excessive force, such as karate chopping, to leave an impression may cause harm -- not to the stamp but to your palm -- and thus is not recommended.