5.4 The Pull-Off video
Tunefox Banjo Lesson #5
The pull-off is kind of the opposite of the hammer-on in that you're starting higher in pitch and 'pulling off' that note to bring you to a lower pitch.
For this pull-off, start with your middle finger on the 2nd fret, 3rd string. Pluck that string with your right hand and with your middle finger, pull off of that 2nd fret to the open 3rd string. When practicing the pull-off, get the meaty part of your finger a little underneath the string so you can pluck a distinct note with your left hand. Just like the hammer-on, this is not a very easy technique to get, so don't get discouraged if you can't get it the first day or week even. The roll we're doing with the pull off is a variation of the alternating thumb roll you know. You'll play strings 3241 and do the pull-off on the first note.
The Pull-Off Banjo video lesson
Play along with this tab to simulate playing with a band. The first measure demonstrates an isolated version of the pull-off and then adds the roll pattern in the 2nd measure.