Ikenai Koto, Shiyo?

Upright, principled, and admired by all, student council president Towako is also infamous for her hatred of guys. The one who challenges that belief is Yui, an underclassman who refuses to back down. When a long-hidden secret of Towako is exposed, the two find themselves drawn into a relationship that crosses the line, a forbidden connection that should never be allowed...!? (Source: MANGA MILLION) *Note: Includes four extra chapters.*