Stash some monopoly money in obvious places, or place your wallet out in the open with nothing inside but a note that says, "u mad, bro?". I'd do that if I were you 'cause I'm a kid like that (( :<
What you need to do is get your own account and keep all of your money in that. And possibly keep your wallet on you at all times. I sneak into my mom's purse to get money only when I am broke because I have bad spending habits, but I am going to stop doing that and work on saving.
Yeah, I don't know what she does that she can't wait til she's at the store for the money. Oh well, I guess. Hahah, I'll take her credit card. Haha, online shopping!!