Oh this.
I LOOOVE to stretch backwards and feel this way for about 5 seconds. It may not be the same effect but it feels so good. I stretch back and my blood rushes all around and junk, and my head feels all light and i almost fall over, but when i do i usually hear a.. almost the sound you hear from a flashbang on a video game. just a loud screech that kind of mutes everything else for a second. at the same time my eyes go nuts and i see almost like the grainy ambient occlusion effect on everything around me. Then it wears off and i do something.
