It's not something I would go search on my own but when I happen to see it online I like it only if there is no romance involved and/or Wendy is forcing him to do it.
I'm not even into femdom or Cartman having sex with women, but if I have to make up a scenario for it, I think the only way I could see it happening is if Wendy still has some unresolved sexual frustration toward him, like when she had that stressy crush on him, and mix it with her hatred towards him.
Something like the breast cancer episode but horny.
Cartman is an absolute pussy when violence is involved so I think he would barely stand a chance and whine all the time, plus he would find it extremely humiliating, which is kewl.
Wendy would feel bad about the "little angry rape" she did and grossed out by having sex with him so MAYBE it would be a one-time-only thing.
Wendy seems "sane" enough to not do something like this, at least more than one time. If that's the case it would just be hetero kyman and I like it gay.

idk if you wanted an answer this horny but yeah.

Also

asked 3 months ago
God sorry I never check this website