The following has certainly happened to many people. You see a famous person and start screaming, but thanks to traffic and other loud noises, that person cannot hear you. Usually a really sharp and loud whistle that is generated by fingers and mouth will do the job.
But what if you don’t know how to do this? This is exactly why we are here to help you with this problem.
Use the middle and index fingers of both hands to form an “A” before placing it in your mouth. The rest of your fingers should be pressed into a fist. This is the difficult part, but you will after one get a few tries.
Touch your lower teeth with your lips. Before doing this, however, suck them in a little. Keep in mind that not every finger will need some space in your mouth because you will only put four of them on your tongue.