Oh, thanks, it actually helped!
I've tried looking at source field on gelbooru before, but now I tried more thoroughly and found a link to the hiccears.com, and while I've also already found Aogami's account on that site before, I was unable to see the drawings themselves. But now that I've followed a direct link to the image it told me why: apparently there are settings for hiding extreme and mature kinds of content (I did look through the settings for that specific thing before, but was unable to find them).
The settings appear to be not linked to the account, but to an "identity" (the site allows you to create multiple "identities" on one account). To access identity settings you first go to the control panel, look for the list of your identities (each represented by its userpic) and above each userpic there's a pencil icon, you click it to go to the identity settings for that specific identity.