Over a barrel
To have someone over a barrel is to place him or her in an awkward or compromising situation. This figurative use dates from the late 19th century and there are three theories about its origin. The first is the early 19th century naval practice of reviving a half-drowned man by placing him head down over a barrel and, by rolling the barrel back and forth, draining the water from his lungs. The second, dating from the same era, is draping someone over a barrel and beating or flogging them as a punishment while the third theory is literally putting someone over a barrel and fastening them there as a prank. The helplessness of the person in the latter predicament makes it seem more plausible than the resuscitation or flogging theories, but none of them is proven beyond doubt.