Reincarnated as a side character in a weird Rom-com manga

Our protagonist, Kimura Takeshi, reincarnated in a weird romcom manga, as a side character.
"My two childhood friends are acting weird!"- this is the name of the manga. A weird romcom in a weird school. But why weird? This is a typical romance manga where the dense MC, Reiji Miyano, have two childhood friends doting for him. His harem includes many other characters too. So why weird?
The weird thing is that the school has a rule: Every single student has to HAVE a boyfriend/girlfriend. If you don't, then the teachers will do a lottery to RANDOMLY choose a partner for you!
Weird school is this! However it's just a manga. That's what Kimura thought. But now he is in that manga world. And he is the best friend of the MC. And his daily life is going to be more eventful than ever!