Secre does more steps than I do. I just gift my side a junk item and use it as a trade. I don't think it makes any difference, but I always put in the trade ad that I'm transferring np to my side accounts just in case they get noticed.
https://www.neopets.com/ntimes/index.phtml?section=522422&week=506
This is old now (four pets on accounts! How quaint!) but it says what you are/aren't allowed to do with side accounts, just in case you want to double check before doing something to make sure you don't get in trouble for it.