SHCHEKOTIKI

'... [a feeling of] half-tingle, half-tickle, when you are trying to remember something or understand something or find something, and probably your bladder is full, and your nerves are on edge, but the combination is on the whole not unpleasant (if not protracted) and produces a minor orgasm or "petit éternuement intérieur" when at last you find the picture-puzzle piece which exactly fits the gap.'

Vladimir Nabokov, Bend Sinister, Chapter 12