Nyuugyaku no Rudbeckia

Mio and Urara, former classmates, became best friends and then lovers. Their relationship continued even after they grew up and became active in national politics. One day, however, a rival senator found out about their secret affair. Wanting to protect Urara, Mio surrenders herself to the blackmailer. The humiliating training play of a noble beauty begins!
(Source: DMM, translated)