When someone defecates grub size pieces of fecal matter into another persons tub. Similar to an upper decker, but more visibly noticeable. The fecal matter resembles a grub, slowly on its way down the reservoir that is the bath tub drain.
Dude, I totally left a tub grub in my roommate's bathroom. He's going to be so pissed if he ever finds out it's mine.
by DoppleGanger14 June 18, 2011
Can you define these popular missing words?