I want to flirt with my crush but he doesn't know how to, what should I do?

I like my crush and he likes me back (he doesn't know it) and I wanted to just get with the flow of the relationship and talk and flirt a bit with him to make him aware I like him but he's a dumbass about it!! Everytime I try to seriously talk to him he just gets too nervous to look me in the eyes and keeps running away/not answering my questions etc.
And then when he starts an interaction or engages in one it gets weird!! He always says something stupid or to purposefuly get on my nerves or try to make me jealous (like, what am I supposed to do?). We end up laughing a lot but that's not really what I'm trying to do DX he doesn't even let me talk for long enough for me to slip a compliment before messing things up. Is he a lost cause?
I want to flirt with my crush but he doesn't know how to, what should I do?
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