It is considered a truism that rape is never really about sex, but rather about exerting power over another human being.
Now, I have no doubt that that's true in the vast, vast, vast majority of cases, but I'm always wary of any statement about human nature that includes words like "always" or "never". Much like a preacher insisting that homosexuality is a choice or an economist asserting that all actions stem from self-interest, I think this particular piece of psychological dogma says more about the person employing it than the person they're describing.
I mean, a dick pops up in front of you, you're gonna suck it. That's just gonna happen. I don't think power factors into it.
Of course, I'm not going to try to claim that specific events like the one Simon describes are statistically likely, or even that a single one has ever happened in all of human history. Leftover Soup has always been about improbable events, improbable events tend to be more interesting than probable ones. Sure, dudes can get sexually assaulted, that's a thing that can happen. We can also get breast cancer, but I'm not running a 5k for it.
Now, that being said, I do agree with Trent here that yes means yes and anything less is no. I recently had someone commission me to draw that Max-clad-in-Post-It-notes-grabbing-Cheryl scene mentioned a few strips ago, and I was happy to take that commission, but I wouldn't take one for the scene described here. Whether it's violent or not, whether the subject is aware of it or not, it doesn't matter - and, like a lot of artists, I don't draw nonconsensual sex scenes.