I get like that sometimes, usually out of frustration... I think I'm bored but it's really my brain pouting because I can't quite do something.
I bought a echo pedal during the last slump. I was eyeballing it at the store, jeering at myself for wanting something I'll never use live. Asked a friend if I should spend the money on something not really made for bass......and the reply was, "If it keeps you interested, it's worth the money". Ding! Pedal came home, slump was over. Something about playing with it helps me get out of my slump....it's just fun. Espically when you set it so its got the reverse feature (you don't hear the note you struck, only the effect...) and try to play ...wheeeeeee. Scales have a whole new sound!
And +1 to trying a new technique....Trying to slap (and figuring out how to incorporate it!) is keeping me interested during the dull times

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Perhaps, since you've been playing a while, taking someone else under your wing? Nothing like teaching someone to reinforce your own knowledge.... and being looked up to is good for the ego .