Lots of normal stuff...?

Sure, but mostly...

You have to be kissing 24/7.

Your lips have to be sticking to his lips all the time like the North and South poles of 2 magnets...

※ This is only Secchan's personal opinion.

But...

Is kissing supposed to be treated so casually...?

Nope! You got it wrong!

Just 'cause you do it all the time doesn't mean it's not serious.