Please help

I'm looking for a webtoon, I think it's shounen ai, and the mc's nane starts with letter D, the plot is like, the mc has a little brother and he met a sunbaenim who throwed up when he was eating out alone, and the sunbaenim turns out to be an alumnus of his school, the mc is struggling with his studies that's why when he learned that the sunbae is smart, when they met at a group gathering, he asked the sunbae to help him in his studies in exchange for what he did for throwing up on him. That's what I remember, thanks.