Okay so, this image is safe, I swear. I've looked at all pages of images tagged 'vomit, safe' and this one is pretty tame, a lot of those even bother me, this doesn't.

Now, if you already know, I made the current vomit tag spoiler image, and I've expressed phobia of vomit in the past. Then why the hell am I vectoring it? Good question, and it's a bit, odd, and fetishy, so it's going behind a spoiler.

So, as a kid, when I was in school, I was downright terrified of being around other kids as I as paranoid of them getting sick as vomit terrified me. I don't know why. I remembered every instance of someone getting sick in school as it ruined my week, nay, it ruined my YEAR and my opinions on that person. I wanted NOTHING to do with anyone who got sick as, to my head, they were bound to do it again, and I didn't wanna risk that. I also didn't like people in general, but hating them due to human biology is a good excuse.
What does this have to do with anything? Well, since I got out of IRL school, and I started growing up, my phobia got less extreme over the years, and while it still bothers me in IRL stuff, in a fictional sense, I've grown soft on it as a whole. Sure, I still don't like looking at drawings of it in many cases, but some I do, and in stories or fanfics I've gone straight into fetish territory for it, also applying to cartoony art depictions of it, much like this vector here.
I still consider that I have a phobia of it, but I've been fighting it for so long, I have a minor fetish for it too. Plus, gross stuff is just fun to make. Really really fun.

As to why I chose him to get sick, well, he's like the ponification of all things gross and disgusting.

Also this with image, I can say that I've used the same 'liquid' pieces for several different bodily liquids, and a few non-bodily. Piss, drool, cum, blood, puke…