Yeah I can be shy if I REALLY like a guy.
It really depends. It depends on:
-How well I know this guy
-Whether I think this guy likes me back
-How confident I'm feeling that day
-What has happened in the past between me and this guy
If I know this guy very well, then it can go either way. I could be more relaxed and LESS shy because I know him so well. OR...if I don't know him well at ALL, I may not be THAT shy because I barely know him and I haven't built him up so high in my mind. So, it really does depend! I'm pretty outgoing normally, so if I'm acting shy around a guy it's MORE than likely it's because I like him.
The MAIN or biggest factor however that determines how "shy" I act around a guy however is whether or not I think he genuinely likes ME back as well. If I don't think that he likes me like that, or if I'm confused as to how he feels about me (maybe he's given me mixed signals in the past), then I will be VERY VERY shy around him. I wont' be able to be myself or fully comfortable. But if I sense that he is as into me as I'm into him, then all bets are off! LOL! I'm not shy at all! I'll be very comfortable around him (for the most part) because I know our feelings are mutual.
How I act when I'm feeling "shy" around a guy that I like:
*I may smile at him in a shy way when I'm around him or if he says hello
*I may act very giddy, silly, and giggly when he's talking to me. I'll laugh MORE than usual at what he says...especially if he's flirting with me
*I may look at him from afar when he's not looking
*I will probably not go up to say hello to him first because I'm feeling nervous, but if he comes to me I'll be very warm, happy, and pleased
*Sometimes I've even pretended not to see a guy near me (not to be mean!) simply because I was SOOO nervous and I didn't know how to talk with him. :(
These are just SOME signs, but all girls are different. Like I said, I'm usually pretty outgoing, so if I'm acting shy around a guy it's usually because I like him. That's not to say that if I'm NOT acting "shy" around a guy that I don't like him. Sometimes I can like a guy a lot and not even be shy around him. But if it's a guy that I REALLY REALLY like, and I"m not sure how he feels about me, or our interactions in the past have been awkward, then I may be more shy than usual.
Sorry this was so long, but I hope this helped!