Insatiable birdie

[Merna]

A sex act performed by [fucking a man] in the ass in [missionary position] while leaning over and blowing him at the same time. It can be performed by either another man or a woman with a strap-on (see Pegging).
The act is named for its similarity to the motions made by the toy heat engines named drinking birds, insatiable [birdies], or dipping birds.