A colloquial term on the internet meaning "mansex" or homosexual male sexual relations. It comes from the term "mansechs", which was (is) a popularway of spelling "mansex" on many internet forums and that bastion of the linguistically adept, IRC.
Him? Oh, he doesn't like women anymore. He has given in to the darkforce that is teh manches.
Name given to the baggymusic 'scene' in Manchester during the late 80s-early 90s. Included bands such as Happy Mondays, The Stone Roses, The Charlatans, Northside. Occasionally some cockney twats like Flowered Up are included under this term. But they shouldn't.
I'm a big geek and I call the music I listen to Madchester!