Is it ok, or appropriate for a guy to ask..?

No, I wouldn't be fine with someone asking me that question, especially if I didn't know them well.  It's none of their business actually and is quite an intrusive question to even ask.   If he asks again, just tell him you don't wish to discuss personal information.  It's quite ballsy of him to even ask you..  Regardless of what anyone may ask you, never feel pressured into answering anything that makes you feel uncomfortable. Just because someone asks a question, doesn't mean they're entitled to the answer.

I do agree.. I really thought he was funny, cool, until that popped up.. and when I didn't respond he asked it again... I just don't know whether to go forward or not, evven just friends

No this is not a person I've known long, it was in a first interaction... 

I think you need to go on adult mug and get off here OK?

Oh sadly I get asked that & a long list of other uncomfortable questions all the time. I don't think that it is okay. I am not sure what on Earth happen to manners & respect but some just don't have it. 

What burns my bacon is when those questions come within 10 minutes of meeting someone.

I am sorry ya had to go through it as well.

I would mind if they asked me ONLY IF we were seeing each other and dating for a while. Other than that, that's creepy as freak!!!

I don't think it's appropriate at any time, asked by anyone, whether you know them well or not.  That's a personal, private and far to intimate question to be discussed between anyone other than the two persons involved.

Private info between friends. If it's someone you just met, it's super obvious where they want to take things next.

"too"

no, its not right for them to ask that and i wouldve told them to mind their own business

Stepper, you think it's an appropriate question for a family member to ask another family member. Personally, I'd find it more inappropriate and considerably more uncomfortable having my father ask me the last time I was intimate, than I would having a stranger ask me. It's none of his business nor is it my business to know the last time he was intimate. What a disturbing thought that is. There are some things that aren't anyone's business, including family members.

Imagining that just creeped me out with regard to my dad, but if my mom had asked me, I probably would have been shocked because she wasn't the type of person that would ask me a question like that, but I would have answered her question after I recovered from my jaw hitting the floor. Lol

Well thats the thing, I know he was being quite flirty, but, should I see it as something that one can just let 'slide', or would you be a bit on guard if someone asked you that ( someone who seemed interested in you..)

It doesn't matter how long you've known this person or how close the relationship is. It's none of his business unless you want it to be his business.  If you want to tell him the day you met him, good, if you never do, it's ok too. 

You truly are something else. How is that question improper. How do know that is not a genuine concern of this person. I don't understand you. I have seen you being so nice and friendly, but then, out of nowhere, like a cat with a hairball, you spit out the most insensitive and vile stuff. Why do you do that?

Thanks NotHarry, I appreciate your feedback. I just felt this is very very soon to be inquiring about when the last time I was intimate... some might (as I did), feel quite self conscious about the answer that you give, being judged.. and it seemed a very private matter to go into on a first talk. Thanks again, now I'm feeling better that when I said nothing, that was ok for me to do.

That is never an appropriate question. If I was on a first or second date I would probably just leave.

You're welcome, just by asking the question, you're giving a stranger too much power. I think.