The off beat pull-off involves picking a bass note and the first note of the pull-off at the same. The pinch of both notes will be on a beat of the bar but the note that is produced by the pull-off is on the following off beat. Study the following example. In the first bar an alternating thumb style pattern is played over an Am chord. The second bar is very similar except a pull-off is played. On the first beat of this bar the fifth and second strings are pinched together. The first finger then pulls away from the second string on the + immediately after the first beat. It is important to let the first note sound for a half a beat and pull the finger away from the string precisely on the +.