cryptic dogs

[poodledoo]

6)......but this is what to do when it misbehaves
20)Tea will brew if and only if this is added for this dog
24)Is this dog a yes man for Nicolas Sarkozy
21)Is the rubbish this dog creates more disgusting than most
no number of letters given

[kayakamina]

Some guesses-
6 Whippet
24 French Poodle
21 Coarser

[spitza]

20 Mastiff?

[rowanwitch]

21 could be Sh1t zhu

[poodledoo]

Thank you for your answers-not sure how your answers to no 20 actually fit the clue, can you explain how you arrived at your answer please spitza & rowanwitch?

[poodledoo]

the answer has now been explained to me, thank you.