When an adult (almost Always Male) expectantly waits for the day a minor (almost Always Female) will reach the age of consent and be fair game for sexual conquest. A key component in any good Wife Husbandry plan. Can become very Squicky very easily. Bonus Points if a daily countdown is kept of exactly how long someone has to wait before they can legally deflower their target. Note that despite the age of consent being under 18 in many places, you can still get arrested for e.g. contributing to the delinquency of a minor, so 18 might still be a good age to wait for.