Apollo didn't like how Ivy tried to stick with him for so long. It was especially because when she stuck with him, she really stuck with him. It came to the point he couldn't use the washroom in private without Ivy barging in.
Feeling like he could no longer have any private space was not only embarrassing, but also demeaning. Sleeping also felt very uncomfortable, as he was not even left alone in that regard.
Though Apollo didn't want to be ignored, he didn't want it to happen like this. He even tried to bring it up with Ivy a few times, but she seemed incredibly stubborn about it for some reason.
The worst part about it was while he was losing sleep, Ivy for some reason seemed to never get tired. Apollo was originally counting on her getting tired enough to sleep, yet that didn't happen, not once.
And so, he resorted to his special tactic, annoying her as much as possible.