Terrible at sexting/flirting

Is anyone else absolutely terrible at sexting/flirting? Like it's an issue. I have a boyfriend and he tries to starting up sexy conversations and my mind just goes blank and go uhhhhh thanks, umm your butts cute too... 
There's an art to sexting/flirting I believe and I just haven't learned it... Which is frustrating because I even suck at conveying when I'm in the mood to have sex bc I cannot flirt worth shit. It's just like sooooo wanna bang? I want to be romantic but I just can't 😞 
Anyone else have this problem?