Just let it happen- sometimes you'll have music already and you need to freestyle words over it, which is cool. Other times you'll have lyrics but no tune to go with it, and maybe you'll hear something next time you jam that will spark an idea. No 2 songs have ever been written precisely the same way. The most important thing is to just let it happen- you aren't making music; music is out there- you're just filtering it through your melodic and lyrical ideas. You can't force that.

I always suggest recording as much of your jam sessions as possible so that you have something to listen to and build on. It helps my band a great deal to work like that, so I hope that's of at least some use to you. :cool:

*gong sounds*