Maku ga Oritara Bokura wa Tsugai

This alpha is the only thing I need... Mitsuki is an idol who hides the fact that he is an omega. In an industry full of alphas, he clawed his way up the ranks and became the top idol at his agency. The next-most popular idol in the game is Mahiro, who is sharp and boasts all the qualities of an alpha. Mitsuki, who doesn't like Mahiro, ends up going on stage with him to help avert an emergency. But, while they are on stage, Mitsuki's medicine stops working and he goes into heat... Mahiro saves the day and the crowd is none the wiser, but Mitsuki is overcome with desires and passions he has never known before... (Source: Renta!)