glasscockis a reference to a pic that showed a female golfer kissing a trophy that resembled a glass cock. Shit loads of people reposted it thinking it was new, whereas in reality it was old and no longer funny. Anything that has already been posted is known as 'glasscock' after this one pic.
(
Rusty Shackleford www.junt.co.uk / @joeyrobbo,
Thu 4 Mar 2004, 21:30,
archived)