create a plane, then a sphere. delete the lower part of the sphere. animate your plane moving 90 degrees in the x direction over 100 frames or so. then select the hemi-sphere and go ncoth> create ncloth. change the preset to lava>replace. the preset button is top right in the ncloth shape node. after you do this select the plane and click ncloth>create passive
right click over the hemi-sphere and select verts, then select the ring of verts that are closest to the planes surface, next select the plane and go nconstraint> point to surface.
this may not be exactly what you are after but it will get you started.