Turning down someone who's been flirting with me
Hello, I'm a female (25Y). I recently joined a new workplace, it's been about 4 months. For context, I don't have any major work experience. Before joining here, I had worked for 6 months at a different organization in the similar work profile. As someone who's very new to the industry, I'm trying to be on good terms with all my colleagues (all of them have more experience than me) so that I can learn as much as I can. There is a colleague of mine (Male, 28Y), who joined a couple of months before me. So basically, he gave me a lot of tips and tricks into navigating the work environment here during my training (I didn't take a lot of them though, because they contradicted my way of dealing things). He's been flirting with me lately and initially I didn't take it seriously, I took it as a banter because we had had an argument after which the banter had started (banters were all in good spirit). I'm someone who laughs very easily, which could come off as reciprocation or blushing. So I'm afraid he thinks that I'm flirting back. It's getting kind of uncomfortable for me because he's openly flirting a lot now and I people in my lab have started to notice and I've sensed them teasing him about it as well but I'm not too sure about it. Lately, even my work friend (Senior, but joined together, female) has started to tease me about it even after multiple communication that I'm not comfortable with her teasing me. Also, I'm not sure but I think I also heard others talk about his supposed girlfriend/fiance in another city whom he visits often.
I really need to do something to stop this behavior but very subtly. I don't want to openly say anything since this is the workplace and I don't really know what to do in this situation. I've been casually trying to say things that are not in his favour so he could get a hint but idk if he caught the hint or no. He also asked to hangout during the long weekend, to visit his place and go to the beach but I straight up refused saying I want to stay home and rest. He's also been insisting on picking me up and dropping from and to the work but I'm not comfortable with that.. he's dropped me home twice but I don't want this to continue. Please give suggestions.