Hmmm. Ironically enough, I also have a two month old and a 21 month old. He'll be 22months end of this month. We've had this same problem, he has no other jealousy issues w/ his little sister, but he wants to be carried when she is or just plain carried from place to place:) All i can say is i have to go VERY slowly from place to place, if he decides to throw a fit (and let's face it, we're at that amost 2 stage so it happens) i continue to hold his hand and just have to crouch down and repeatedly tell him to stand up and walk w/ mommy., it takes awhile sometimes. I've occasionally walked a couple steps away if it's a safe place in order to imply "well, alright if that's your choice then you're going to be left behind." When I'm out somewhere i try to remember to bring the front pack carrier thing for my infant daughter so if my toddler gets out of control i can quickly pick him up to cross whatever hallway/crosswalk/doorway his tantrum is blocking and locate a good place for timeout (time out is our response to a fit.) Another thing that works well is trying to make him feel like a big helper, if i give him a book or some item or other to carry in somewhere for me he's usually a lot more agreeable about not being carried since he's being a "big boy". Also, if it's time for a snack, that keeps him pretty destracted and he forgets he wants to be carried. As i said it's getting better but there's still those days when i wonder why i thought errands would be a good idea w/ two small children. lol