So there's this girl I met on a field trip in university. I did not give her that much attention and I played my game right. I did not want a relationship or any type of commitment. In other words, I just needed pleasure (sex).

I took her phone number by the end of the field trip (by her asking for it) and did not talk to her.
One night out of nowhere, she calls me and tells me to go to a pub. I refused her offer several times but then I thought to myself "hey I don't have any early classes tomorrow, so instead of sleeping I can go and have a couple of drinks". I arrive there, she was with 2 other girls. We started chatting and I was the most active on the table, making friends with the whole place even the waiters (guys) and bartenders. I know that all they wanted is for me to hook them up but I didn't care since I had the high reputation in the place.

Couple of minutes later, we start dirty dancing and in around 40 minutes, we start kissing and touching (from the outside). However, that night only ended by kissing. I started going out with her for a couple more times (kissing) and touching from the outside; however, every single time I try to undress her bra (in the toilet of the pub) she lowers my hand and says she'd only do that to her Boyfriend and starts asking me if I like her. I DO NOT want a relationship but I just want to have fun with her. She keeps asking me if I like her and I do not know how to respond back. I do not want to say yes and get stuck in the relationship zone.

You didn't qualify her man. You gotta qualify them regardless of whether you want a relationship or not.

It sounds like you want her for the short term, which is fine, but it seems like you need to communicate it a little better. Instead of not responding, it may be better to tell her something like, "obviously we like each other a lot and I would love to keep on seeing you, but I don't wanna rush the whole boyfriend/girlfriend relationship thing after only 1 day. Let's just keep on having fun and see where it goes." That may get you a lot more respect and give her the validation that she needs.

Two subtle things I threw in there was the use of using 'we' -- I like using 'we', because it puts her in a frame where she is agreeing with you. Also, "love to see you". Chicks really connect with the word 'love', even if you're not telling them that you love them. Think of it like push-pull.

Anyway, hopefully this helps if you get stuck in this situation again.

Thank you very much. I think this is the exact type of information that I need.
Thanks again.