2. A euphemism for a furtive romance, usually one centered around hot and dirty sex.
3. A common misspelling of Killing Aliens.
"Where are Matthew and Melissa?" "They're playing Halo."
B: Unfortunately! Oh, my eyes...
2)having sex in a dark room where you're not supposed to
3)hanging out with a member of the opposite sex under false pretenses of playing a popular video game
Guy 2:"I'd love to, playing halo is the shizzletobisquitshit, are you hosting?"
Guy:"I'll host like always you scavenger"