I'm glad you had a good first outing with your kilt. It's not something you wear to blend in! Have fun with it.

To answer your question, some sporrans make a little noise, some make a lot, and some are quiet. The ones with a hard face almost always "drum" in my experience. I don't like it, but many guys do.

If it's driving you crazy the simplest thing to do is put a dab of glue(I used hot glue--it holds fairly well and didn't damage the leather) on the backside of the tassel to immobilize it. It doesn't take much to hold it down, and you definately don't want it to show. You can also hold it down with a hidden stitch, but sometimes that's pretty hard to do, especially on really hard or thick leather.

Your only other options are remove the tassels or get another sporran. Removing them is a matter of personal taste since they serve no real purpose beyond decoration. Of course, having another sporran would be nice too. I have a Buzz Kidder that I got from SWK that I wear a lot. It has a ton of space, looks good, has no tassels and it was only $55.

If you like the drumming don't sweat it. Just consider it your own personal drumline.