Yes, in some situations. No, in others.
Allowed:
- You may use your side account to bid if you are legitimately transferring NP between your own (main and side) accounts.
Not Allowed:
- You may not use your side account to artificially increase the price of an auction, whether it is your own auction or another player's.
- You may not collude with another player to manipulate the outcome or final price of an auction.
These rules apply regardless of whether you are using a main account or a side account.