The body's natural opioids to make a person feel happy! Also to reduce pain. The only place these are found naturally is in the bloodstreams of people who are in love, in diet sodapop, & in chocolate!
Someone who's intensely, happily sated, such as after great food or sex, to the point that they can't do anything more than flop around.
(As used by Elsa Moriarty in cracked.com's "The 6 Most Counterproductive PSAs of All Time")
"You're spent after most anything fun, from sex to exercise to an intense round of Mega Man 2. That satisfied, post-coital and -foodal period is one of the best parts of the experience -- when every desire has been sated, and you're so happy you can do nothing but flop around like an endorphin walrus."
Your body's natural pain reliever, released when stress or pain levels are high, or after an orgasm.
Equivalent to a narcotic pain reliever once released.