what I'm looking for is manly guy being raped.
the person being raped must be masculine, preferably with a six-pack. but not necessary hairy or fat. (I'm not particularly looking for a bara)

just someone who LOOKS like a seme, being raped

This fits your request: Kyokan Hunter . Well, it's not the violent type of rape, because I resonally never enjoyed that thing so I don't read it, but it's more than dub-con (almost non-con) at the beginning. Enjoy!

Lemme see...
Shigekiteki na Kankei and Motto Shigekiteki na Kankei
Jive, though I still can`t tell if it was noncon or not 0_o
Fuhoni, though the uke never actually gets raped, but comes close
Ch 1 & 6 of bousou kareshi coming really close to rape, but being saved by semes :3
Eien no Tameiki, the uke likes it, but the seme kinda, uh, knocks him out :#
In jazz the seme ALSO knocks him out( seems to be a seme thing) and it starts out with noncon
In Sono Kuchibiru ni Yoru no Tsuyu is extreme noncon, but the ending is cute :3
Anyways, that`s all I remember, hope I helped.

Devil’s Thoroughbred, maybe? The seme tapes the whole thing, uses it as blackmail. It's really short though. I'll update if I remember more.

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There's no other way in the world ahead ♥

ohhh I love this kinda topic

Hua Hua You Long
Kuroneko Kareshi no Asobikata
Ubawareru Koto Marugoto Zenbu
[m]Devil's Thoroughbred[/m]

I know I read more, but I just can't remember them Dx