I never thought of Using HP thunder knuckle feint to do anything but cancel from normals and seismos. In this video [media=youtube]wlcX0RV1kfQ[/media] you can see that you can use it on wake up if timed right to avoid a jump in just like if you were to use a ex seismo feint but the fierce tk cancel has 6 frames of full body invincibility, recovers faster than EX seismo feint, and uses no meter. ALL credit goes to Javitz and Andre Lambert aka twisted jago for finding this out.
If anyone finds any more uses for this trick please post it in this thread.
what i have found is that you can use the hp tk feint to avoid a jump in from most characters and avoid the OS sweep, and that sweep might be punishable from that close. Heres a video I made showing an example [media=youtube]isQYCT02Q4o[/media].