it was clearly done for shock value and it completely undid any of Jaime's positive character development. it was just really gross and unnecessary.
apart from that scene, I enjoyed the rest of the episode. Tywin's scene with Tommen at the beginning was fantastic. Charles Dance is pretty much the best. I'm really excited for the rest of this season. Tyrion's trial should shape up to be pretty damn good. oh, and why was Oberyn wearing pants during an orgy? wtf?