Where can I find the most helpful Slapbass lessons or tips on how to double thumb better and whatnot? Thanks
Listen to The Beatles, Pink Floyd, or whatever you want to listen to.
Dreams/Celestial Voyager (My Band's recording )
Live at Pompeii

Put this in your signature if you think coalition governments in democratic societies are f*cking retarded.
just keep practicing whether it's any song (with slap or without) or just messing around, it's not that hard really.
Once your fingers toughen up it'll get easier.