@venelizapariat says:
"Bam ja mo" literally means having rice on a stone slab. It is part of a culture practised by most Khasi-Pnar families. Family members gather around a mortar and pestle (we use a huge stone slab) after the making of a delicious side dish famously known as "tungtap" (fermented dry fish). What we do is we mix leftover rice, so as to clean the stone slab before we wash it (God forbid we let anything go to waste!). Everyone digs in and if you snooze, you lose. Sadly, it is a dying culture seeing as it is easier to just dump everything into the grinder. Sure, it saves a lot of time and energy but the effort put into making it by hand makes it all worth it. For some reason, it tastes better!