My not single co worker said he could guess what colour underwear I was wearing?

I work as bar staff at a restaurant and my co worker who’s the same age as me (early/mid 20s) is also one of my supervisors. He has a girlfriend he lives and bought dog together and all that. Despite that he’s still asked me some very questionable questions or said strange things like asking if I enjoy being single, guessing how many people I’ve slept with, saying he can guess what my type is, saying he enjoys being in a relationship despite admitting to having been a manwhore and sleeping with 50+ girls before girlfriend. He’s asked me to rate him out of 10, so I asked back about me and he said 8.

I though some of these interactions was just the work environment I was in and that he’s an incredibly social person but today he said he could guess what colour underwear I was wearing, saying red (wrong), I asked the other girls and they said he’s never asked them that before. He does like to wind me up all the time and see me get annoyed and likes to joke that I have a crush on him just because I said my type is Latin looking, dark hair & eyes, thick dark brows and that. I don’t feel that way towards him and I wouldn’t entertain it in that way if he tried anything. He’s not “physical” but he likes to steal pens and my phone from my butt pocket all the time. Reminds me a bit like a little kiddo who has a crush, but I’m so confused if he’s just being friendly or actually likes me? He does enjoy making me laugh as he’s quite funny, but I don't know what to think of it as we’ll talk pretty openly about sex life and his and his girlfriend sex life even? (Which doesn’t make me feel uncomfortable, it’s just kind of unusual).
He’s just being friendly
Vote A
He secretly likes you but is in denial because he has girlfriend
Vote B
He likes you and is trying to pursue you
Vote C
He just likes attention
Vote D
Other answer
Vote E
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My not single co worker said he could guess what colour underwear I was wearing?
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