Majime na Kimi ni Hamaru Karada THE ANIMATION

After entering college, Azusa Shirakawa was enjoying campus life, marking a fresh start from her high school days, when she had devoted herself entirely to judo. But a casual joke from her childhood friend, Sae, ignited a fire within her. “Having a friends-with-benefits relationship isn't so bad, you know?” She had brushed off those words as a joke, but—her “one-time fling” with Takuma, her serious and sincere childhood friend, awakened a desire within Azusa, and her body found itself unable to resist the pleasure. Contrary to her intentions, she found herself losing control time and time again. “I never thought the day would come when I'd be getting my body in shape not for judo competitions, but for sex...” She, who was supposed to be so strong-willed, finds herself “losing” to a man. He—serious yet lecherous—begins to “corrupt” her.

(Source: Pinkpineapple, translated)