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."
Yur always very entertaining, Ruth! Unfortunately, nothing seems to do it to me anymore, except exhaustion from work.