The Son

The slime hops down from the window and crawls under one of the room doors which just so happens to be the son's bedroom. The room is dark but the slime notices a light coming from the son's bed. To get a better look, the slime crawls closer and leaps onto the foot of the bed. Once on the bed, the slime slithers closer to the unknown source of light and is confused by what it sees.

The source of light was from a laptop and the son was currently masturbating to porn on screen. It looked like he had just started so he hadn't gotten very far. The slime had no idea what this human was doing or why it was doing it, but that's what it was here for. The slime wanted to know what was going on in the humans mind, so what better way to do that then by entering him. The slime was set to get inside the son, but where to enter?

The son's mouth?

The son's ass?

Maybe the son's penis?