Grooming isn't dating a child...that would be pedophilia. Grooming is when a person builds a relationship with a child, young person who's at risk and that's exactly what happened Mizuki built a relationship with a four year old child and continued said relationship.When that child came of age he started a romantic relationship with him.Their age difference is 12 years actually and I could get past if the seme didn't make weird comments like "i've raised him well" and the "badump" when he was proposed to by a child just adds to it.
He clearly said he saw him as a brother till the time Kotaro came of age. Haven't you ever been confessed to by little kids or seen some kid do it. Anyone would find it cute, its just cute. Nothing else. That's what mizuki felt when kotaro was a kid. If it was grooming Mizuki would have always thought that he'll date kotaro when he grows up even when he was a kid. But it's not like that
I rly tried to look past the age gap thing but they keep mentioning every chance they get bro and I rly can't. The fact that he knew him since he was a child and waited till he was an adult is the literal definition of grooming. This could have not been weird if we had just never brought it up again but for some reason it's like the author's purposely trying to make it weird bro. Like every chapter he keeps reminiscing bought the good ole days when the ml was a toddler??? Thats weird?? It's way too groomey for me man I'm out