PAIS-035 Invite your friend to fuck your stepsister

The number of people with experience is 1, exactly 1 time. When she lost her virginity, she squirted, soiled her boyfriend's room, and was dragged away. Since then, I haven't done H, and I feel complicated. Not only that, she doesn't like having big breasts, so she is a meek girl with her head down. I applied because I wanted to change myself, but...