1. Commonly used as an insult among teenage boys.
2. To flubbergust is to place something edible, into a females
vagina, have sexual intercourse with the item in the
vagina, and after orgasm, eating the edible materials out of the
vagina using your face.
3. A mildly painful, yet rewarding method of "freak sex" exploiting a woman's vagina with foreign items which are later eaten directly our of her by the partner.
Here's a fubberguster situation, where Joe is the flubberguster.
Joe has a cup of apple sauce. He pours it into Jane's
vagina.
Joe then penetrates his
penis into Jane's vagina, and has sexual intercourse until orgasm and ejaculation.
Upon ejaculation, Joe will remove his
penis from Jane's vagina, and use his mouth and tongue to eat the apple sauce out of Jane's vagina.