Doo doo butter is a yellow-ish and brown semi-liquid secretion from the anus. It can be caused unannounced from having too much anal sex, i.e (the anus becomes loose and open where when you walk the buttox will generate the anus to motion and thus leak). Sometimes during the act of anal sex doo doo butter will slowly ooze out of the anus during the intercourse.
"Damn La'Tonka! Your second-cousin's baby's mama's sister in-law, Sharilla sharted some nasty doo doo butter on me after I gave that ho a good ass invasion!"