Teemo adc can sometimes be tough to get away with due to toxic team mates. Never play teemo if
-people are already arguing in champ select (no need to make it worse)
-the enemy jungler is ap
-your team has an ap top or jungle

The pros of playing adc teemo
-hybrid damage
-easy to punish your opponent's bad positioning
-deny farm with Blinding Dart
-safe and fast split pushing due to Noxious Trap
Cons of adc teemo
-you will get flamed in champ select
-Because teemo takes ap blues over mr blues you are vulnerable to ap junglers
-hard to trade vs a caster adc like corki or kog'maw

Use your NOXIOUS TRAP spell to trap all of the entrances into bot lane for safe split pushing
Try to q+auto attack the enemy adc as they go for a creep to deny them from farming it
Harass as much as possible in lane