Our 2y old is getting naughtier by the day: he would slam our moving door back and forth damaging the wall, jump on his baby-sister and so on. We tried to pick our fights and only discipline him for what we considered serious violations, i.e. ignore when we plays with the food, throws his teddy bears in all 5 corners, etc.

Discipline currently means a clear warning/No and announcing the consequence, and then follow through with a timeout if he continues.

He clearly gets the concept, since every so often he tells us 'No' before he does the action in question. Every so often after he did it, he would come to us and say 'Sit' and walk to his timeout corner. So he is kind of asking for the timeout and seems to rather enjoy it - which in my mind is a bit counterproductive.

He did this before and since the arrival of his baby sister and he gets plenty of attention - though invariably less since his sister arrived - from his parents (story times, play times, etc) and my mother in law plus a helper.

Initially we just thought to let is pass as a phase but it's now almost 3 months and no considerable change.

Any views or tips?