A "Huuuuuuummm"
when having fast, hard sex and the penis pulls out to quickly for you to stop the momentum of it missing the vag hole and hitting the boney part of the vagina...there's only one word for it.
Matt was hard at it, smashing the granny out of Betty. Yet things came to a sudden stand still when he yelped A "Huuuuuuummm" Betty was gutted.