I would recommend using Warwick wax. Once the surface is clean and ready to be finished, it's pretty much idiot proof to apply. Apply a generous amount to a large clean lint free cloth that has been folded several times. Heat the wax and the cloth using a hot plate - I use a George Foreman. Once the wax is melted and the cloth is hot, simply rub it into the body and the neck. Rinse and repeat until you have applied it to the whole of the body and neck and it looks and even colour(the oils in the wax will darken the wood slightly as they are absorbed) make sure to keep the cloth hot as you apply the melted wax - the heat will help the oils penetrate the wood. Leave the bass for a few hrs to allow the oils in the wax to soak in to the wood and then do it all again.
After 24hrs use another clean lint free cloth to wipe off any excess wax - you can also then polish the finish or not depending on how matt you want it.