When losing a game hard.
When you're losing a game hard, regardless of your roll. Be it top lane mega tank, mid lane hyper assassin bot lane sniper elite, bot lane's sacrificial lamb, or glorious jungle. Then you see that the enemies are 15 kills ahead camping you in spawn and have baron elder all your towers and 5 zed's flapping their weird arms at you. You gotta stay positive, just know those other guys can make a mistake. Maybe you play too defensive and their carry gets cocky and tries to all in someone, lock him down pick him off and repeat or engage.
Now that's how an average player does it, but if you want to know the secret way and take it from me (dude who's been reported more times than the bible's reality has been questioned.) First take 40% attackspeed with 1% crit into your rune page. Then pick a champion who has insane jungle clear time. Shyvana, Master Yi, Tryndamere, Kindred, Kog'maw(yes this broken 5.0 attackspeed can do any roll) Now that you have a good champion and runes of insanity, buy the attackspeed jg item and, this part is important. GET THE RED VERSION. Sorry if that sounded angry you need that red smite. Now you choose a lane, any lane, preferrably bot lane, two enemies, two bodybags of free money. Camp that lane until they ragequit. Now you get a stattik shanker, triforce of power, blade of %damage, and swifty boots. Last item optional I take BT to solo baron. Now go into a lane and just rush towers and become the split pushing legend.
Note: This was all written for good fun, if you adopt these tactics you will most likely be reported for carrying too hard.