Lately I've been asked to sing lead on a few songs while playing bass. I have always been awed by players like Geddy, Sting, Phil Lynott, Chris Squire...guys who are excellent players and can sing while they're playing. I must have some kind of mental block when it comes to this because for the life of me I can't coordinate it. Now, I admit I do not consider myself a lead vocalist, but I do it out of necessity when called upon and always sans bass. When I sing backups I need to dumb down the bass lines as much as possible to be able to pull it off. Can anyone offer advice on the best way to practice this? I always seem to automatically gravitate to either the bass line or the vocal line at the expense of the other. Do I need to partition my mind somehow to think in two directions at once or something?