The Toughest Guy in School is an Omega!?

Under the country's law, omegas are obligated to wear a chastity belt. A rumor is going around that there's a key that will unlock the belt, and people are fighting to find this key.
Sashima is the toughest delinquent around.
An elite group of alphas, the Snakes, hear about Sashima and come to fight him.
The leader of the Snakes, Aoda, is expecting a big, towering man, and while the Sashima standing in front of him has glaring, piercing eyes, he's also short... and an omega!
After telling Sashima that he chooses him as his partner, Aoda suddenly grabs Sashima and starts kissing him.
This Aoda is out of control! Sashima's right-hand man, Taketora, has also been pulled into this whole mess. Who's going to be the one to soften the toughest omega?