The yukkuri are naked and are rubbing up against him; not exactly sex, but we don't have a tag to describe yukkuri's engaging in sexual activites with humans. furthermore, the look on the guys face implies do not want; though we'd need a full translation to get an idea of whats going on. (personally the art style is crappy enough to warrant a "do not want" but I know my preference doesn't count)
This doesn't count as humansex because, as you said, there is no sex. There is the stupid_sexy_yukkuri tag for this, I just forgot to add it. As for the do_not_want tag, there isn't a clear definition, so I just removed it like a joke tag. I let that tag alone in posts that are either creepy (although we already have nightmare_fuel for that) or boner killers (like post #34574).