yea, you can sponsor someone so you could pay with another account as a sponsor.

All you do is delegate an extra 60sp from whatever account you want to be the sponsor then if you send a wallet transaction from the sponsoring account to @themothership (i think .001 will work) and in the memo field you put this:

$sponsor @username

So if you were to do this from your main account and wanted to sponsor @thehive, you would delegate an extra 60 sp from your main account, send a wallet transaction to @themothership and the memo would read:

$sponsor @thehive

This will use 60sp delegation from whoever sent the wallet transfer to @themothership as a sponsor for whatever username you use

If you are a member and have side accounts you can also just delegate 60sp to @themothership with your side accounts.