Hajimete xx, Kaimaku shimasu!

Tsubame has one ambition in her happy days with her boyfriend, Maharu: "I want to have sex with you, but...." yes, Tsubame is still a virgin! Tsubame is in agony with her unlimited sexual desire and dream of having her first experience, and one day she makes a big decision to ask Maharu out on a sleepover date. She asks him to spend the night with her, and he says, "If we spend the night together, something is bound to happen!"
Tsubame invites him to bed with full of expectations, but what happens?