A local matriarch has taken the concept of "filial piety" to a new, voyeuristic level.

Mdm Tan insisted that her son-in-law's bedroom stamina is a "family matter" that requires her direct supervision.

She reportedly monitors the nightly activities from a 4K monitor in her living room, occasionally shouting advice through a megaphone.

"Eh, why you so fast one? Like that how to get grandson? Use more power lah, don't be so weak!"

The couple has been forced to sign a performance-based contract where "satisfactory completion" is rewarded with extra chicken rice.

Experts suggest this is the only way to solve the national fertility crisis without government interference.

"My mother-in-law say my strokes not efficient, must follow her auspicious rhythm or else cannot," says victim Kelvin Lim.