A crichothyroidotomy is performed by making a vertical incision over the thyroid cartilage (forms the majority of the adam's apple), down past the cricoid cartilage(if you slide your finger down the middle of the thyroid cartilage, you will feel a soft spot and the another piece of cartilage - the softr spot is the cricoid membrane, the other cartilage is the cricoid cartilage). You then incise the cricoid membrane which lies between the two. Using the other end of the knife handle , insert the knife handle into the opeing and turn about 90 degrees to enlarge/dilate the opening - then either place an endotacheal tube, or some other tubing into the opening directed downward - give a couple of breaths & listen for breath sounds - equal breath sounds is ideal.
I wouldn't suggest anyone trying these techniques w/o training, but in a last ditch effort...
You can also place a 14 gauge angiocath percutaneously through the cricoid membrane (again directed downward) and push oxygen through it at a very high rate - can often buy you some time.