Bassline help

Me and my mate jam alot he plays guitar but its not liek rock music or anything its either funky or peaceful picking style and he always makes my basslines for me which is annoying but its because I cant do it he doesnt just use root notes and it always sounds good but if I attempt it nothing comes into my head. I can learn songs I play all sorts but when it comes to makign my own it just dont work.

I really want to get some creativity working I just find its easier to make something up on a guitar than a bass but I dont want to give up bass its something I want to get betetr at but at the moment this makes me want to put it down for good.

What helps use make up your own bass lines? we dont have a drummer just a guitar and bass.

Playing whichever notes are in the chords your guitarist friend is playing is the safest bet. If for one bar he's playing C minor, you can play C, Eb and G. If for the next he's playing Eb major, you can play Eb, G and Bb, etc.

If I had more time I'd write out the tab pattern, which is much easier. I don't, though... so I'm hoping someone else will

Here's how I do it:

I check, or ask, what he's fretting. For example he says C. Ok. I start in C and stay on that single note untill I get the rhythm down. Usually I add a fifth (G) or the octave for effect, but I always end up on C. This gives a very basic pattern. Then I ask him if it's a minor or major chord. Then I expand by using notes from the corresponding scale.

If it's a chord progression (G, C, D, F) I do the same for every chord. Start by following with just the root notes until you are comfertable, then expand.

Of course, if the guitarist is a more experienced musician, maybe you could ask him "how the heck do you do that?"
Unless he's arrogant...or too eager to show off...then he won't give you any proper tips.