It is a a handwoven mat usually used for sleeping/resting/laying down/playing tongits or pusoy on.
This type of mat is traditionally made in the Philippines out of dried stips of buri.
Fuck if your filipino you must know what this shit is!
"Hey papi, let's go to the beach, don't forget the banig and the cards!"
"We forgot to bring our air matteres to the campsite so we had to sleep on the banig. I had itchy lines on my arm the next morning."