Mean spirited Australian (or at least Melbourne) schoolyard slang to express one's enjoyment over a friends misfortune or suffering. Similar to the German word 'schadenfreude'.
When someone sucks so badly and they say "that sucks dick," that really isn't a bad thing. However, no one wants to get their dick sucked with scratchy braces.
Football QB metaphor applied to dating meaning to get told by someone that they just want to be friends or don't like you back, before you can make a move or ask them out.
In football, when a QB gets tackled before he can leave the pocket created by his linemen, it's called getting sackedin the pocket.