Its very normal between guys, and certainly not completly unheard of between guys/girls.
Teasing is a big part of flirting for most guys/girls, especially teenagers. And what your describing sounds like physical-teasing. My business works with kids as they grow up through their teenage years, and you can pick the boys out, when they are still kids, that will go on to be good with girls. At that age they don't understand flirting and there is nothing romantic there at all - but they get teasing. They tease the girls, and the girls play up to it and tease them back.. 3 years later when they are teenagers, its those same boys who are the ones who have now transitioned their teasing into flirting.. being playful.. etc.
But some of that childish teasing stays. The main reason it works so well is because its a sign that the guy treats you like an equal. You don't playfully tease people who are bellow you. You help them, you bully them, you pity them etc. You don't playfully tease people who are above you because your scared of their response... you tease people who are one the same as you, and who you are close enough to trust won't react badly.
So when a guy teases a girl as part of flirting, the signals he is giving out are very possitive for girls. he is saying (through his actions):
1, hopefully we are close enough that I don't fear your response
2, I am confident enough that even if you respond badly I can handle it
3, I don't think I am beneath you, or that I need to worship you and fear you
4, I don't think I am better then you, and that you should be grateful for having me
5, I have enough social skills/ability to make you laugh and to make us both happy
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So if you have a guy who is teasing you and flirting with you.. and you like him back. Brilliant, sounds like a perfect combination! Go have fun.