Backstory: We’ve been colleagues for around ten months and get on very well. It’s an informal, hipster type work place and all of us on the team tend to socialise together. Him and I have genuinely become friends and enjoy each other’s company. He’s always been very respectful and polite and we are both quite reserved people unlike the rest of the team who are more extrovert. We’ve never ever had any reason or cause to discuss sex.
This is our first week back at work in person and today we were having lunch together outside and catching up. My eye was a bit watery from hay fever and he leaned over and kind of put his thumb next to it as if looking closer and wiped a tear away that was running down and then commented it was a bit red looking in a concerned, caring sort of way. Then, really bloody randomly while he still had his hand near my face he said, really seriously
Have you ever let anyone cum on your face?

I was really shocked and told him it was none of his business and not ok to ask me something so personal. He laughed and said “is that a no, then?” and said it’s the kind of thing friends discuss and he didn’t know why I was being so weird.
I don’t really have anyone to ask this in real life as it’s quite embarrassing but AIBU and weird. Or is it just not alright for someone to ask you something as graphic/sexual as that? As I say we don’t have a friendship where we talk about our sex lives or anything remotely sexual.