An "orangutang bang" is polyamorous sexual activity undertaken by a individual caucasian female and a troupe consisting of three or more negro males.
So from my room I heard someone say, "Put that big thing in my mouth". I then walked to the kitchen where I found my roommate and several of his friends along with a redhead from the swimming team ensconced. In general terms they were engaged in what could be described as a gangbang. I was invited to join however, I turned down the invitation. Later my friends termed what was occur to be not a "gangbang", but an "orangutang bang".