>>30780
Not really
>>30778
You can definitely tell when someone is ejaculating (and this is widely attested anyway, so it'd be odd to disagree even based on second hand knowledge) and you can definitely tell when fluid drips inside your anus if it's substantially different in temperature, forceful, or causes a pressure differential. Whether something like picrel or the loads of common domestic/barnyard animals, even larger prosaic loads are more than enough that you can tell. Given the sorts of proportions and volumes depicted in hentai, you'd definitely be able to feel the ejaculate beyond just the sensation of your partner ejaculating. Plus, the 'pleasure of being cum inside' probably refers to the former (and thoughts associated therewith) moreso than the feeling of the fluid anyway.
>women cannot sense semen entering their vaginas during ejaculation
This is mostly the saying of catmoms who've never had good sex and can't feel their pussies anyway. It's incoherent because you can super obviously feel someone cumming so you wouldn't know whether you can feel the cum or not because you wouldn't be able to extract it from the more obvious feeling since the depths of the female reproductive system are pretty insensate. You can definitely still feel e.g. a horse (even something like a miniature) or a dog even then not to mention you can super obviously feel ejaculate with the more sensitive parts of your anatomy. Are you going to tell me you can't feel it if you splash warm water on the outside of your rectum?