A fork of Rural Dictionary
To watch a large amount of a geeky television show, episode after episode, for a long period of time. A season of Buffy in two days, for example. Similar to marathoning movies or chain smoking, but more geeky.
"I just mainlined the first 3 seasons of Angel" "I'm going to go home and mainline the LOTR movies." "Wheres Ferg at?" "Oh, hes at home, sitting in the dark, mainlining Simpsons episodes"