2.5 years old is so young! It does sound like he's looking for positive one-on-one Mommy attention rather than intentionally trying to tick you off, but I'm sure there's lots of that even at this young age, too.
My nearly 9-yr-old (middle child of three) is an expert at "playing dumb" both at home and in the classroom. Our attachment therapist has advised us to have the teacher quickly attend to her attention needs as they come up, with a physical touch to the shoulder to calm her, then walk away and let her do it herself. "A, I know you can add 3+4 since I saw you do it correctly all last week. But it's OK, you can stay in for recess and finish your work in the office if you need to." (So far A has been spending quite a few days inside during recess, so I'm not sure how well this method is working.)
At home, the therapist wants us to recognize that when she gets whiney "I'm hungry" (10 minutes after eating an after-school snack), "I don't know how...," and other babyish things, she's "asking" for one-on-one Mommy-"baby" attention (because she missed these as an infant & toddler). Therefore, Mom (or Dad if he's there) is supposed to pull her into my lap and spend a few minutes "teaching baby" the missing skill. The therapist said she'd only need this a few times for the brain to re-wire and that she'd ask for it (or show a need for it with misbehaviors) less and less until eventually the behavior is gone.
This seems to be true for the food issues so far. I began hand-feeding her pretzels or snap peas, etc. (with her lying across my lap on the couch) when she says, "I'm hungry!" within minutes after eating an after-school snack, and she hasn't complained of being hungry for a few days now. Hmm, maybe she's moved beyond that one!
Meanwhile, she's still getting two or three "warnings" at school each week, so it's clear her needs aren't being met there.
Just a thought...maybe baby him a bit, lovingly re-teaching skills you know he already knows...and with Attachment parenting in mind...verbally expressing that you are being a "good Mommy" because "good mommies teach their babies xxxxx" (this is to help him distinguish good mommy-you, from neglectful/hurtful mommy. Eventually he'll see you as two separate individuals and hopefully quit acting out with you to express his anger at her.)
Good luck! I know we all need it!
EDIT: RE: Lorraine's tricks...Yes, those are great! We've done that as well with our "baby," but when she's fighting with her sisters and creating all kinds of havoc in the next room, I'll have her sit on a blanket in the room with me (usually the kitchen because they always act out when you're busy, don't they?!) with baby toys. This keeps her close and out of trouble, and most importantly, BORED. Then after supper I'll take her aside and ask how she liked sitting on the blanket with the baby books and blocks. She'll admit it wasn't much fun and she'll try harder to think before acting next time. HOWEVER, our new therapist said that she won't ever be able to process this and make those connections (behavior to consequence) until we re-wire her thinking by showing her she's loveable, deserving of affection, and we'll always be here to care for and love her. Tall order, but we're just beginning, so we've still got lots of hope!
