Well, let's suppose that Clark stays with Kon for as long as he can but, ultimately, the poor guy has a day job to do: so let's say he leaves his sleeping son his work, cell and home number with some of kind note saying "I have your costume--you're grounded, call me."
So Kon calls his work and long story short, it ends up a little bit of 'scene'--not enough to be a shouting match or have anyone fall out but, ya know, enough for passers by to get the picture--teen trouble. So Lois comes on over all too curious with a pretty simple intent: Wanna talk about it?
And then from there we get the revelations and Lois declaring herself Kon's mom