That would have been even more perverted, but maybe it was just too much. Though from the butter dog gag I don't think it is.
Edit: thinking about it, maybe that was the joke, she expected the ink to come from down there but instead it came from her mouth.
I got the feeling she got the image of someone who knows nothing about sex, and it doesn't even cross their mind, like with Edo. Combined with the age difference she may feel like she's in love with a child.
I know it's just him being obsessed with underwear, but he also violates social norms and personal space. If I have a mosquito in my ass I don't want to be spanked even if you had the best of intentions, you ought to respect my space and boundaries around my body.
His exclamation feels a bit like a lunatic speaking: people stop leaving his camp I have seen through your plan!!
Though seen from another perspective, people going to work on a foreign netural/unknown-intention camp and not coming back could be interpreted as them being kidnapped/killed.
Maybe the author simply doesn't know about brain tanning. In the wikipedia page it only appears briefly mentioned, but not explained. Maybe we are the weirdos.