so i am now in jazz band (school started 2 days ago, im a freshman) and ive been playing since 6th grade. I play outside of school and focus on that most, and usually play to my ipod through an ihome because frankly, i havent gotten to play with my friend yet. There is a junior who plays the bass with me, who, in somewhat of a joking way, can act like a jerk. Anyways, we sit next to the drummer, and the two will start playing random stuff (drummer will come up with a beat, he will play) any good ways to "come up" with something on the spot? he can make it sound good, i feel like if i did it i would embarrass myself. Clearly i should just practice, but any good tips that could help?