At the very least you should do some prototyping of your product (not idea) and do some basic market research. No one wants to buy an idea but they might be excited about a new product that needs their capabilities to bring to market.

Market research will tell you a lot about how the idea might have been tried before.

From my own perspective you sound like you’re describing a partial glove. I believe these have been tried before but maybe there are some new factors that make it more viable. That idea does have traction with artists using touch screens for drawing because it neatly solves their problem.

Im not even sure how to go about prototyping this, not without spending a lot of money to get there. Not a glove, but more like a custom formed mouse shell, thats at least as big as the users hand.

Theres definitely a market for it. People have made all kinds of ridiculous mods for their mice to make it comfortable, and then theres mice that come with a billion parts that allow customization for your comfort. This would give a better option, and allow choice of mouse based on pure performance, instead of having to compromise because of feel or comfort. As far as i know, nothing like this is being done for mice, but the technology to make it already exists in other markets

Perhaps you have a Makerspace nearby or similar setup, those places offer a lot of expertise and tools to help get started. Prototyping also involves going a bit MacGuyver versus trying to build the final product you have in your mind. For example if there is a lot of custom forming involved your initial tries could just be made out of plaster of paris and chicken wire. Likewise you can use manufacturing techniques that wouldn’t scale to the final product but would be cheaper for a one off.

I'd learn how to model the thing and 3D print it (if it's solid). Not that expensive.

I seen it’s already been suggested by others, but I would have also recommended doing a prototype, and then pitching your idea to investors. This involves doing your homework. In addition to doing market research which has already been suggested also do your research on who you’re pitching your idea to. Know your audience, understand what they typically invest in, why/why not, things that motivate them, and their values etc and then you tailor your presentation to them.

Here’s a book you might like to read if you’re full of ideas you want to make happen:

The Design Thinking Playbook: Mindful digital transformation of teams, products, services, businesses and ecosystems by Michael Lewrick, Patrick Link, & Larry Leifer.

It’s not the be all and end all, but it’s a really easy read and good place to start for acquiring the knowledge you need for developing an idea, prototyping etc.

I'm not sold on your idea mainly because for me, to avoid RSI in the wrists, I've found the cheapest wired mice to be the lightest and thus easiest to move around avoiding RSI strain. Since then I've found out an increase in Manganese can help protect the cartilage on the bones and bones in the wrist.

But if you insist.

Identify the companies you want to take on the considerable expense of R&D and manufacturing, and will hand over a slice of their profits to you for just having a brain wave.

Compose and send them a nice letter if you feel generous enough and committed enough to invest in the cost of a stamp, if not send them an email.

Wait and react accordingly.

Do you have a timeout setting?

If you want to have a monopoly on the idea, file a patent, in every country, but beware patents can be expensive to file, and the lawyers defending them can cost even more. Cue Abba's Money Money Money, to help that sink it. ;)

The idea im having would not add much, if any, weight to the mouse, and in some cases might even lower its weight. At least in my initial vision, the mouse upper shell (and possibly buttons) would be replaced with this product, and would be formed for the users hand, in the users "comfortable" or most often used position.

Heated mousepad with some glide layer for the mouse to glide easily. Also, one might think of a sort of a glove in which one slide in an have a physical connection with the mouse

Ideas are just a multiplier of execution

https://sive.rs/multiply

Good luck