When does it get clingy or desperate always starting the conversation?

So I like this guy that I'm friends with, and I find myself constantly wanting to talk to him so I usually start the conversations. It might be through SMS or Facebook or even in person. When I do he responds well but he never starts them...which leads me to think that he is no that into me, he doesn't think about me during the day enough (or at all really) to actually text me...the thing is he is really flirtatious with me and does it openly, and when I do start the conversations he is really into them, we talk about everything and laugh a lot...so basically my questions are: does he seem into me? And secondly when is it too clingy to always start the conversation? Is he seeing me as desperate? And lastly do guys realize if a girl is into them? Thanks for reading guys!
When does it get clingy or desperate always starting the conversation?
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