Have you ever felt high after sex? Floaty and foggy and a little unsure of your step? Maybe you, as many are purported to do, just roll over and go to sleep? Have you ever lost your short-term memory?

Did you just do a double-take?

A 54-year-old woman stopped into the Georgetown University emergency room because she'd lost her memory. She remembered who she was, who her husband was, where she lived. She even remembered having sex with her husband the night before. But after that, nada. Not even the memory of curling up next to her man and falling asleep.

Turns out this isn't all that uncommon. Sex can wipe your memory clean of everything after the fact and make it impossible to make new memories. It's called transient global amnesia, and doctors say it's probably caused by sexual undulations that tighten the lower abdomen. Well, that and faulty valves. And memory returns, generally after a few hours.

“We don't know very much about the cause,” said Sebastian Ameriso, a neurologist at the Institute for Neurological Research in Buenos Aires, who was not involved in the 54-year-old woman's case. “It causes a lot of alarm, but this is not a stroke or an event that causes damage to the brain. It's almost always very benign.”

However, they think it may be blood that has been sapped of its oxygen being forced back into the brain by a combination of tightening of the vessels in the abdomen, and weak valves in the jugular being unable to prevent the back-flow.

But please! Do not avoid having amnesia checked out, no matter how much sex you've been having. Your doctor beseeches you. Memory loss is also often a sign of stroke which requires immediate treatment to prevent permanent damage.