Kimi to Dakara, Zenbu Shitai. Ai de Tagari Kare no Amai Yokkyuu

Konami Satsuki is an office lady who is insecure about her large breasts and tends to slouch. She hides a secret from her fellow female coworkers. She's dating her superior who is popular with everyone, Sudou. Both of them share a similarity, their fondness for a mascot, and start dating. But until now, the furthest they've gone is just kissing. Being the gentleman he is, Sudou patiently waits for her to consent to taking the next step. But because of certain circumstances, they get into a disagreement. Satsuki tries to get away, but Sudou wants to love her wholeheartedly.