How to deal with co-worker who I suspect is being vaguely condescending?

So he’s 19 and I’m 25 and we’re both dudes who work in the same department together in a supermarket. I’m 6’1 and he’s 6’3 (height is relevant to story).

He only started about 6 months ago but is a generally gentle & shy guy (and even a little socially awkward). Because we work in the same department we’re both accustomed to each other.

For the most part, I do think he’s a stand-up guy and a top bloke.

But his immaturity does get on my nerves from time to time. There’s a lot he still needs to learn, but whenever a cute girl appears he likes to project as if he’s in charge and start dishing me orders (as if I don’t already know what I’m doing). This admittedly only happens whenever girls appear so he’s mostly good, but I do notice it every time because it does come across as quite emasculating… *(I don’t need a kid bossing me about every time he sees a cute girl).*

And all I can really do is say: *”Yeah, Bob, I don’t need to be told what to do. Just focus on your own tasks”.* But it doesn’t stop him from engaging in this behavior whenever a pretty face appears.

As I said earlier too, there’s a height differential between the two of us (with him being a number of inches taller). And so I’ve noticed that whenever a cute woman starts talking to me, he’ll come over to us and put his hand on my head and start petting my head like I’m some kind of cute little pet dog or child and say *”Good boy hehe”* like it’s some buddy-buddy schtick. But it just comes off as incredibly patronizing & emasculating. Especially since he only does it when women are around.

Like he’s trying to highlight to everyone our height difference without verbally saying it. I don’t touch other people so it actually really does annoy me when he invades my personal space to do that. But I’m afraid that if I tell him to stop doing that I’m going to look like I’m being dramatic…

It’s even more ridiculous because of our age difference. It just seems like a disrespectful thing… I can’t imagine ever thinking this is normal to do to a high school teacher just because they’re shorter than me.

And whenever I try to make conversation with him he’ll find a way to relate it into me being ”old”. Like we were talking about English and he was asking me about some word, and I explained how it’s Old English, and he goes ”Oh, because you’re so old, of course you’d know Old English”

Normally, I wouldn’t mind this if it were just someone being playful and trying to get a friendly reaction out of me. But this side of him only ever shows up when women are around. Like he needs to knock me down a peg in any way imaginable. And always in the most passive & subtle ways.

Any ideas or suggestions on how to deal with this?… I suspect he’s young & naive and doing this behavior on purpose without realizing how transparent it is.