Ok, I know the type of cassette you're working with then and yeah, it will probably be easier to pull it off to grease the bearings. Check out Sheldon Brown's link
on cassette removal tools for freewheel hubs to get an idea on what tool you will need.
It helps to have a vice and a chain whip to tighten and/or loosen the cassette. You can use an old bicycle chain held in a vice grip as a chain whip but I don't think they're that expensive to buy. I bought a $33 bike tool set
off e-bay which includes a chain whip and many tools needed for working on bicycles the same time I bought a Park Tool PCS-10 bike stand. The bike stand isn't really useful for working on motorbikes (I bought a 6' folding table which works much better for this) but I have a few motorized bikes I fiddle with too.
Amazon has many chain whips in the $15 range including one that also works as a peddle removal tool.