Today, I'm recommending a blog.
No, don't stop reading! It's a really cool blog, honest. It's called Male Submission Art. (Link is NSFW.)
It's not completely m/m. It's a mix of male/male, male/female, and solo male art. But even in the heterosexual pictures, the focus is on the guy.
The fellow who runs it, maymay, created the blog because "there is not enough porn wherein submissive men are the erotic subject matter". IE, porn focuses too much on women, so maymay decided to even things out a bit by showcasing hot guys tied up.
Some of the art (like the most recent image) is more philosophical than hot. Most of it is both. The blog is no longer being updated, but it still has fifty-something pages of art.
Look at this! Isn't it just gorgeous?