A portable information handling system having a cooling airflow vent located in its bottom surface extends and retracts feet at the bottom surface to aid airflow when the portable information handling system is rested on support surface to impede airflow through the vent. In one embodiment, a microfluidic reservoir communicates pressurized fluid to the plural feet to extend the plural feet if a predetermined thermal condition is detected in the portable information handling system, such as a predetermined temperature, a cooling fan that initiates operation or an impedance to airflow through the vent.