Poodle-flaps is a term used to substitute a swear word when cursing. It is often used when under the influence of cannibis, and can be a response to something that you are incapable of formulating a lucid reply to. The term conjures images of a Poodle's vaginal flaps, and this is the intent.
Bob: "James, pass the pringles..."
<knocking over the pringles in an attempt to reach them>
<Upon making an error in work or college>