Asking the important questions here!!!!!
I think its pure shonen-ai in the novel, but the manhwa isn't going from the same path as the nove so we're expecting some 18+ hehe
it's shonen-ai. both manhwa and original novel However, there are new side stories from the novel and it's 19+
It's mostly kissing VERY INTIMATE KISSING A LOT OF KISSING
but the side stories will be them being domestic and being freaky
novel readers, did they fuck? or like shonen-ai