have you seen the manual therapy video of Marc Heller, DC
the technique is excellent but be cautious!
1. do not use it in acute & subacute manifestations
2. read the course of sciatic nerve again
3. understand the meaning of each step of the manipulation
finally i would recommend that it should be used after the normal SLR is re-gained in a prolapseIVD. i found it responds well to conditions producing restriction of glide where the root constituting the sciatic nerves are not impinged within the TV foramina.