The fetish is "male lactation". Very weird! The art style seems to be geared toward women readers, so I am assuming that is who it is for.
Porn comics have to be creative -- so obviously some crazy fetishes will come out of it. Naw, I don't think it's a "sign" that women's sexuality is progressing. There's been crazy fetishes expressed for a long time. I think fetishes are pretty different than girls being more open to having sex, which has happened in recent decades.
I think the main thing that will progress here in the US is where it'll be more like Europe.... where the negative stigma of rolling in the hay will lessen among women, and society won't have an anti-woman/casual sex issue (not much more than the negative on men which is much less).