Okay so I feel this is a pretty used up subject, but I'm feeling a tad lazy and making a new one. So whenever I play with either friends or myself, my plucking fingers and the top of my forearms starts to cramp up, making it that much harder to play. I can't really have that happen, because I play a lot of metal and punk. The position I have when playing is where the top of the bass body touches my belly button and I hold the neck diagonally to my body. Any suggestions on how I can play longer and easier without getting all these cramps and such?
Ideas: Raise the body of the bass a little. Don't play with so much tension. Warm up before playing fast. Stretch. Ice. Rest. Develop a lighter tough.
Sounds like you're tensing up while you play. You should be really relaxed. Another thing to consider is your hand position. Could you describe your hand position please? Edit: To add on to what ii7-V7 said about warming up, how do you warm up and stretch before playing? If you it's recommended to do so before each time playing.