CUSTOM FIT YOUR THUMB TIP
You asked: "Is there a way to make my thumb tip fit my thumb better?
Why, yes there is!
I custom fit every thumb tip I own, and I own a LOT!
The thumb tip is the one magic prop I use the most. I have one in every pocket, in my glove compartment in my car, in practically every drawer in my house, and even out in my barn!
It's the best "go to" when I want to entertain someone with some magic on the spot.
The video shows you exactly how I custom fit my tips.
Now, I custom fit them to make them MORE SNUG.
I have found that it is nearly impossible to make them LOOSER without ripping them or damaging them in some way.
So if you need a looser tip than you have, I would suggest buying a bigger size, or learning to use it so that it rests farther up on your thumb above the knuckle.
As for the color, this is always a subject of lively discussion.
Some magicians try hard to get a tip that "matches" their skin tone.
In my opinion, it is better to learn to use the tip properly, so that it remains hidden, rather than try to fool people with a tip of the "same color" as your thumb.
When I do lectures, I use a bright orange tip to make the point that it's not the color of the thumb, it's how you handle it.
It's worth the extra effort and practice to learn how to properly hid the tip- any color tip!
The hot water trick works, but not quite how people think. First of all the water shouldn't be BOILING, if you have a microwave with a "Beverage" setting that's best. Second, you don't want to put it on a broom stick or anything like that, you should carefully put it on your thumb (another reason not to use boiling water, so you don't burn yourself). What you're really doing is not so much altering the Thumb tip's size (it may stretch or retract a bit but the difference is negligible) as it's shape, like personalizing a mouth guard for sports. Fingers aren't perfectly round, and this can help make a tip that just slightly doesn't fit to work better for you because it's more custom fit to the shape of your thumb. If you don't feel the need to do it then I don't recommend it, and this tape trick seems like a great solution, and can make a much bigger difference overall.
Overall, its a great "tip"!