Told me to put it in gameplay so I will! *Miniacal laughter* Possible Jhin Build.
- He does indeed have a mana bar! and with no real attack speed he probably uses abilities a lot, CDR may be a good way to go!
or 
- Crit and attack speed, they go into your damage output, but that sweet sweet move speed from these two items and from all your crits and your items, as well as getting more of that CDR from ER. Runnans may or may not be able to apply 4th AA on hits.
- more bang for your 4 shots.. longer range Why not? by this item you should have 30(35)% cdr.
- You now have 40-45% CDR, Spam 10 teemo shrooms across key areas where you think a teamfigth might happen go somewhere secure when it happens Press R and MELT SOME FACE OFF!
Like if theres a teamfight about to happen at mid, place E traps on the sides where people tend to walk a lot, go into raptor pit, press R Boom boom boom boom!. Done. Won team fight. and skip your merry way to the deserved 5th Dragon buff...
40-45% CDR? how will that help?
Q will then have a 4 second cool down... YOU COULD SPAM YOUR GERNADES
w - 8 second cool down ZAP EVERYHTING and make sure you do it better than 
e - You can now perhaps have 8-10 TEEMO SHROOMS ON THE MAP!
r- Is now up every minute by late game they could die, walk back to lane, and die again as they sit there and say "WTF IS THAT COOLDOWN?"
(no longer stacks with 
, you're simply not going to be able to stack it up quickly enough to be able to use it effectively.
I'd suggest 
, which is another very useful item for his 4th auto), they spread to those additional targets. If you can't get a quick death, might as well make it bloody.
— wait. Last Whisper. 4th auto Guaranteed Crit. AD that scales with AD, AS, and Crit Chance.
, 
/
, 
(which gives him some bulk while also giving him that burst damage and additional Movement Speed).