No, one i-pill (levonorgestrel) cannot be relied upon to protect you from pregnancy for subsequent acts of intercourse, even on the same night. Emergency contraception is designed to help prevent pregnancy from the intercourse that occurred before you took it; it does not provide ongoing protection. For any further intercourse tonight, please use a barrier method like a condom to keep yourself safe. If you have already had another unprotected act, please consult a healthcare provider for personalized guidance.