I just think they're neat

Kind of an odd question but does anyone have suggestions for how to like... "paint" a stuffed animal? I have a custom plush that was missing some details that are personally important to me, I just want to add some simple patterns on it. The material it's made out of is basically faux fur, so I need something that can reach downward into the fur and not color just the tips, but also not clump it and cause it to be less soft. This plush is never going to be washed due to it being very delicate so it doesn't need to be waterproof. Specifically I'm looking to add deep black onto a light brown base so I don't think I can use chalk which is a suggestion I've seen previously

I've seen people actually airbrush certain paints but when it comes to more of a fur texture I've seen people who do custom furbys and fursuits recommend brushing a Rit Dye or a fabric paint through the areas you'd like to color gradually. Either way if you paint your patterns on a wire brush will break up that hard paint on the surface for a better blend and better texture

update on this guy, I totally botched the second eye but it's alright. I stepped back and regrouped now I'm gonna go at it again with a different method