Play a champion that doesn't rely on auto attacks and has a gap closer. The biggest reason Teemo top is good is his blind and his fast movement speed.
Yorick: High harass, Has a slow and a speed boost, and sustain. Shuts down Teemo hard. Use ghouls to push Teemo off all that farm and if Teemo risks the farm drop everything you got on him and charge at him. He can't blind you + 3 ghouls (+ your ult if you thin you got him) I'd also run exhaust on Yorick to really lock down Teemo.
Rumble: Spell based, has a nice speed boost and the slows from harpoon. Teemo's blind is useless on rumble besides being annoying. Yes he is ranged but if he goes in for CS/Harass you can hit him with harpoon, pop W shield/speed boost, and flame spitter him to death.
Most AP Tops are pretty strong vs Teemo due to the use of spells and not relying on auto attacks.
Hope this helped. Have fun!
EDIT: If you really want to play Wukong vs Teemo. Bait some harass out of him with your clone then Q + Hop onto him, or Q + Hop then clone out fast hopefully before his blind comes out or he does a lot of harass. Just play a bit aggressively on him and less on farming. Mercury Treads help remove some of his DoT and Blind damage.
Best Answer
You cannot drop the aggro once you've gained it since the turret has True Vision and you become stealthed with your W and not Untargetable.
Your clone works pretty much like a Mordekaiser Ghost or a Shaco clone. It counts as a champion but also as a pet which puts it pretty high on the priority list of turrets.
The only way to get the turret to focus your clone is by using the ability right before the last of your minions dies. Also keep in mind that any damage to a champion before or after you cast your spell will let the turret focus you again which requires walking out of range in order to drop aggro.