I've done this project several times with 10th graders. Have to supervise
closely and warn them of any "goofing off" and consequences! Wet paper towels
on the face instead of vasoline also work well. I heard a horror story about
the suction the vasoline creates around the eyes. Instead of straws in the
nose--one wise guy poked the straw and caused a nosebleed--I have the students
roll a cylinder (about one inch in diameter) with paper to use as a breathing
apparatus. It creates a better breathing passage and also creates some
interesting "expressive" mouths when dry.