Billdillbadack Share definition Flag An abnormally large black dildo. "Yea, so I walked in her room and saw her masturbating with a billdillbadack!!! How did she fit it up there?" Billdillbadack by Laljdeofa February 5, 2009 0 0 Get merch Get the Billdillbadack mug. Buy Now — $32.95 See more merch