When popping a stick of chewing gum in your mouth ask yourself a couple of questions first.
Is it possible to chew the gum and NOT chew with your mouth open? This is a very serious question. There are a number of people to can chew on a piece of gum and never blow a bubble, never make the gum pop and never, ever chew with their mouth open. Keep in mind, however, that this number is very few. Even if you are relatively sure that you are NOT someone who does any of the above, it's quite likely that you are indeed a gum-popper or mouth open chewer and just don't know it.
Will you be talking on the phone while you are chewing the gum? Talking and chewing gum, even when the other person cannot see you, they can hear you. Just like eating and talking on the phone, people know that you are chewing something because, well, there is something in your mouth other than teeth and a tongue. There is something that is going to cause you to lisp or sound like you have a bit of a speech impediment. So although you believe that you can disguise it, the person on the other end of the phone line will know that the gum in your mouth is causing you to sound odd, which will be distracting to them.
Do you anticipate talking to anyone face to face while you will be chewing gum. This is HUGE. If you are going to be talking to anyone you should not be chewing gum. All the reasons stated above fall into play here. I am surprised how many corporate executives who had had too many cups of coffee will chew on a stick of gum prior to a face to face meeting and not spit it out before they begin talking. The result in a lot of head nodding, smiling with gum in your mouth, laughing and then having to chomp on your gum enough to get it back to where you can manage it. Problem is, you aren't managing it. You are chewing with your mouth open in front of other people. There is talking while balancing gum between their teen and way too much chewing with their mouths open. While you would not eat dinner with clients and chew with an open mouth, it's unnerving how many will talk to the same clients and chew gum.
Reasons for chewing gum are to freshen breath or just keep boredom at bay. These are good reasons to utilize a stick of gum. But unless you can keep your mouth closed while chewing and not sound like you have something in your mouth while speaking, don't keep the gum in your mouth while you are in contact with anyone else. Try a mint instead. They take care of coffee breath and disappear after they've done their job. You don't have to wrap a mint in a piece of paper and you don't have to dispose of it in the trash. This is not a reason to abstain from gum chewing. It's just a way to not annoy those around you.