[TemporaryMail]

That's another way yes and I've actually seen another site do this, but I wasn't able to find it in my browser history.

[terrycody]

Maybe you are referring to https://www.emailnator.com/, it utilized that trick

[TemporaryMail]

Exactly, that's the site I had in mind although I'm pretty sure it had another name before (could perhaps also be the reason to why I didn't find it in the first place).