I would also say the "it" that follows, the monster, is an embodiment of contradictory social pressures that follows women in the contemporary world. The pressure by men to have sex (and the rewards that come when you give in to that pressure) vs. the opposing social force condemning you for being a sl*t, saying you are just sleeping your way up catching up to you. This is represented by the chain of sex, it both damns and then saves you. The first person you fuck damns you (you lose your virginity) and the second person you fuck saves you, but at the expense of you damning them. They become the "sl-t" that society chases instead, the lowest rung in the totem pole.

I think it's a quite poignant and thoughtful criticism and exploration and has a lot more nuance than the user above gives credit for.