In a partnership situation how does one hide ones donation withdrawl in bank account info. I've seen using cash back in stores a few times a week until at adds up to a requested donation vs straight bank withdrawl which would set alarms off.  Does that sound about right? Any other ways around it?

You get Cash Back shopping at stores? Lucky you. Most places I've been to don't give Cash Back. It's best to get your own Back Account. This way your SO won't suspect anything.

Do you also hobby?

A couple other things that can be done.  Take out "spending" money weekly but don't ever spend it, instead put it into a hobby fund.  If you have accounts at 2 different banks, write a check for cash in some oddball amount ($123.67) and then cash it at the other bank.  Most bank statements won't show who the check is written to, so you could say you paid a medical bill, or for car maintenance, or your kids school expense, etc.