im yet to get a review first guide and not sure how does this work...., on few words...

ROA gets you tons of hp (because of passive), AP for poison (steady damage) and a 1:1 fling
Sunfire= armor + HP, more steady damage
Force of Nature + tons of HP = you won't die
last item, Rylais Scepter is situational, if everything goes wrong glue + slow from poison and get out of there (ghost+force of nature+ult = none will catch you)
even if someone those, you can fling them and they are slowed again :)

some little tips...
everything is about the way you move, how and when do you run toward enemies (sometime just to make them thing you want to fling them) and get some creeps through poison, etc

be creative for the 6th item

singed is a very fun champ to play try him once and you will love it

just note.... move runes +4.5%, masteries +3%, boots, force of nature +8%, ghost +40%, 2 ranged slows (exhaust, glue), mobility its the name of the game

Armor and magic resist enough said

1/14/15

Attack Runes
Exhaust, +0.5s. multiple uses, stopping karthus ult, kats ult, the carry, slow etc... i love exhaust