Honestly it didn't even occur to me it could be a spoiler until someone in comments said that.
It's literally a 1:1 copy of a scene from another show, art style is way different and I think I saw that scene remade to different shows like 5 times already. It's a popular meme. I said I'm not 100% sure because I didn't read the manga so I don't know what wacky stuff the author put in the story though I think I made it clear it's unlikely he would repeat a joke from the other show 1:1.
Since then I also found the original source and put it in the description so yeah 100% it's just a meme.
As for if they're dating or not idk but god damn I hope they are! Their chemistry is just too good.