Bokura to Usagi no Koi wa Sensou
From Hoshikuzuu Scans:
The ordinary Santarou has an extraordinary secret. And it's that he gives off pheromones to the boys around him. His childhood friend Sukai, transfer student King, classmate Mimi and even Tomomatsu. He's used by them over and over again! B-B-But, this won't do! He's not some sex slave! But it feels so gooood...