Reddit reviews Permatex Clear RTV Adhesive Sealant

Buy any pair of decent in earbuds. Instead of using the foam inserts that they come with, buy a moldable earplug kit (like this one) and create your own. They will fit perfectly without pain for long periods of use and will be extremely secure.

Here's a video of someone doing it. And if your molded earbud needs any repairs, since they're silicon, you can use any silicon sealant to fix them. Like this one.