A woman whose vagina is used at such an astronomic rate that no matter how many times she chooses to shower or douche she's left with huge amount of excess of sperm, making her vagina a semen storage device. Seminal fluids typically rival water levels of the Hoover Dam. A Sperm Aqueduct should not be confused with its little sister the "Sperm Bank".
The term Sperm Aqueduct can also be used with homosexual connotations also. SEE EXAMPLE 2
2: Billy’s is such a homo that his ass is becoming a sperm aqueduct, like his mother’s.