It feels more like a story about student who was manipulated by his childhood crush (the teacher) into sex. Notice how the kid changed and became more gloomy after what happened, the teacher almost pretended like nothing happened at all. Syundei's works are usually dark or twisted (except for Nakamura-kun), so it wouldn't surprise me if this was meant to be disturbing too.
It feels more like a story about student who was manipulated by his childhood crush (the teacher) into sex. Notice how the kid changed and became more gloomy after what happened, the teacher almost pretended like nothing happened at all. Syundei's works are usually dark or twisted (except for Nakamura-kun), so it wouldn't surprise me if this was meant to be disturbing too.