There's sex you wish you could forget about, and then there's sex so good it blows your mind and you can't remember it. Seriously.

It's called transient global amnesia -- it's temporary, and it can happen after vigorous exercise, hitting your head, or having sex. These activities cause a change in blood flow by creating pressure in the brain's blood vessels. This, in turn, causes a lack of blood flow, which makes the region of the brain responsible for recording new memories, the hippocamus, incapable of doing its job. To put it simply, you have such a mind-blowing orgasm your brain stops working, and it's going to be awhile before it starts again. People with a history of headaches or migraines are more likely to experience TGA.

The good news is it's a short-term condition and does no real damage -- the only thing lost because of TGA is a few hours of memories ... so hump away!