Ok, when I first saw that someone had entered this as a goal, I thought to myself that this was silly.
Then I reconsidered and remembered how long it took me to learn how to whistle, and then how long it took for me to learn how to snap my fingers (which I still don’t do very well).
So, I can say that I can do this, and have been able to do so since I was a child.
I’m not sure that I recall this as being something that took me too long to learn, probably taking a part of a summer when I was a child.
I think that the first secret is to ensure that the gum is mostly sugared out, or that you’ve chewed it enough to where the grainy sugar parts have left it and now it’s smooth.
Then, to blow the actual bubble, be sure to use your tongue to push outwards in the middle while holding the rest of the outer part of the gum with your mouth.
Once your tongue has pushed the gum outwards a bit to make it thinner and to allow a place for the air to go, start blowing while moving your tongue slowly back. Make sure to keep a hold of the outer rim of the gum with your mouth.
That’s about it, and the rest will just come with practice.