Why would a bright kid go willingly to punishment? Be real! R., I know you are trying your best....so, place the child in a corner where you need not lift! Sit and face him, at a stare. If he rebells, shove him back to the corner and say you "will not receive (whatever it is as a SURPRISE) as a reward as good boy...favorite toy, no sweets, please! Remember, good behavior also gets set for timer! He needs to hear "good boy!" more often.
Actually, child care is much like training the dog! At this age, if you can afford one, get a smart dog from the FPCA...a very small one, please, good with kids as a recommendation. Try this on trial with an adoption agency of animals if possible. Yes, the dog needs attention, too...but the child will project to the dog's habits as you train...all in the family!
No cats...cats cause allergies. Make certain the dog such as a hound or sweet disposition of a cocker spaniel is welcome. It will certainly divert the problems.
Speaking of problems, Becca...take away all the potential situations that cause mis-behavior...within reason. Raised two boys of very different dispositions. Busy minds need to be entertained by pop-up books...go to the library soon! See what inspires without too much stimulus. Too much causes confusion and frustration. Three books back, max!
Good health to ALL of you...keep your sanity! Baby.