He does seem to know what he is doing,and yes,I would say it is due to you exspecting.
Peeing is not as uncomfortable as running around with poop in the pants,so he is using this as an attention getter.
While I do approve and use spanking for very serious disobediance,I do not use it for potty mistakes at all.
Now that I have said that,my advice would be to start using plastic pants over his underwear,this will help contain his accidents and will not be very comfortable for him.
If you wish to try this for one week and see how he reacts,if after the week and he has not improved,we will switch to the three strikes and see how that works.
Please let us know if you try it and his responses.
Sarah, Hi and welcome to the Toilet Teaching board.
The previous poster had some great ideas. I also do not recommend spankings or other punishments for accidents, as that is a negative reinforcement. Some children will have accidents for extra attention, What I do recommend is when your DS has an accident have him clean it up, change his own clothes, put them in the washer/hamper or where ever you would like them put. I hope that helps. Please keep us updated on your DS progress.