The term pound sand originally referred to the degrading job of filling rat holes with sand. However, its meaning has evolved, it now refers to a technique used in Vietnamese
whore houses. This technique was used when the whores would give a man a hand job and then right before the man would ejaculate the
whore would cap the penis, give it one
hard pump, and then release it causing the man to ejaculate with such force that the it would hit the ceiling.