Need help on "I'll Be Your Baby Tonight"

You might be referring to the string muting I do by placing the palm of my picking hand lightly on the strings right near where they cross the saddle. I explain this in detail on my "Easy Steps to Guitar Fingerpicking" and on other fingerpicking lessons as well. Aside from that, I can't think of anything else I do to get what you call a "choppy" sound. 

It sometimes takes some practice to find the "sweet spot" where the notes are damped but still have some tone. Work at it a while and you should be able to get it.

I hope this is a help to you. Let me know if you have any more questions. 

hi,

 I am watching Happy's Seven Classic Dylan Songs DVD and practicing. I made through "Dont Think Twice" and very glad I did. But I am having trouble on the 2nd song "I'll Be Your Baby Tonight". The problem is I can not make the choppy thumb alternating sound. I practiced the index/middle finger strumming as shown in DVD but that's not what Happy's doing in his performance. My question is how to make thumb alternating choppy? I noticed Happy is doing some sound stopping using left and right hand, but he was not teaching that in detail in DVD. Do I need some other material to just practice that ?

thanks