Callback humor is talking about something you two discussed that was either funny or interesting. If it was something funny, you’d text her about whatever it was that made you laugh. Any type of text would work. All you’re really doing is bringing up the good emotions that were released with whatever that subject was that caused the humor, thus making her recall a pleasant memory and associating that memory with you.
You all seem way too needy. It’s okay though, we all get that sometimes. Work on improving yourself first, before you try and bring another person into your life. Sure, easier said than done and we all sometimes crave the opposite sex. it’s natural. But overthinking and over analyzing every little thing you say, or every little thing she/he says is slowly killing your chances. This is hard to overcome, I, myself am still working on it constantly.
A lot of these one liners are really good for text messages, but you really need to do a lot more than just a one liner to set yourself apart from the rest. Remember, today’s dating world is fiercely competitive and guys are up against a lot of other guys competing for the same girl all because it’s so convenient to get in touch with one another. Online dating is just making the situation even worse, when anyone with a selfie can sign up and get spammed by hundreds of suitors in a few seconds. Keep these in reserve for after you get to know someone. The funnier ones especially: who doesn’t like to laugh?